Home
Search results “Select partitions oracle”
SQL Partition By Explained
 
06:42
Using Oracle's SQL, I'll explain how to use Partition By. This will be similar in other SQL engines that have the Partition By keyword.
Views: 35297 Pretty Printed
Oracle Partition By clause, Oracle Analytic Functions tutorial
 
09:09
More about analytic functions, visit https://www.youtube.com/watch?v=Ukekis8C-SI&list=PL99-DcFspRUoscBHdh39T8EHENfm2VcQ3&index=2 Oracle Analytic Functions and Over By Partition clause enable calculating cumulative and moving aggregates returning multiple rows for each group.
01 Overview of table Partition in oracle
 
07:26
Partitioning enhances the performance, manageability, and availability of a wide variety of applications and helps reduce the total cost of ownership for storing large amounts of data. Partitioning allows tables, indexes, and index-organized tables to be subdivided into smaller pieces, enabling these database objects to be managed and accessed at a finer level of granularity. Oracle provides a rich variety of partitioning strategies and extensions to address every business requirement. Moreover, since it is entirely transparent, partitioning can be applied to almost any application without the need for potentially expensive and time consuming application changes. Partitioning allows a table, index, or index-organized table to be subdivided into smaller pieces, where each piece of such a database object is called a partition. Each partition has its own name, and may optionally have its own storage characteristics. From the perspective of a database administrator, a partitioned object has multiple pieces that can be managed either collectively or individually. This gives the administrator considerable flexibility in managing partitioned objects. However, from the perspective of the application, a partitioned table is identical to a non-partitioned table; no modifications are necessary when accessing a partitioned table using SQL queries and DML statements. Partitioning Key ======================== Each row in a partitioned table is unambiguously assigned to a single partition. The partitioning key is comprised of one or more columns that determine the partition where each row will be stored. Oracle automatically directs insert, update, and delete operations to the appropriate partition through the use of the partitioning key. When to Partition a Table ========================== Here are some suggestions for when to partition a table: Tables greater than 2 GB should always be considered as candidates for partitioning. Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month's data is updatable and the other 11 months are read only. When the contents of a table need to be distributed across different types of storage devices. When to Partition an Index ============================= Here are some suggestions for when to consider partitioning an index: Avoid rebuilding the entire index when data is removed. Perform maintenance on parts of the data without invalidating the entire index. Reduce the impact of index skew caused by an index on a column with a monotonically increasing value. Partitioned Index-Organized Tables =================================== Partitioned index-organized tables are very useful for providing improved performance, manageability, and availability for index-organized tables. For partitioning an index-organized table: ============================================ Partition columns must be a subset of the primary key columns Secondary indexes can be partitioned (both locally and globally) OVERFLOW data segments are always equi-partitioned with the table partitions See Also: Oracle Database Concepts for more information about index-organized tables System Partitioning System partitioning enables application-controlled partitioning without having the database controlling the data placement. The database simply provides the ability to break down a table into partitions without knowing what the individual partitions are going to be used for. All aspects of partitioning have to be controlled by the application. For example, an insertion into a system partitioned table without the explicit specification of a partition will fail. System partitioning provides the well-known benefits of partitioning (scalability, availability, and manageability), but the partitioning and actual data placement are controlled by the application. See Also: Oracle Database Data Cartridge Developer's Guide for more information about system partitioning Partitioning for Information Lifecycle Management Information Lifecycle Management (ILM) is concerned with managing data during its lifetime. Partitioning plays a key role in ILM because it enables groups of data (that is, partitions) to be distributed across different types of storage devices and managed individually.
Views: 7494 Md Arshad
Local Vs Global Partitioned Index in Oracle 11g
 
17:30
The Video Explains the difference between Local Partitioned Indexes(Prefixed vs Non Prefixed Indexes). and Global Partitioned Index along with the challenges in maintaining Global partitioned Indexes when the underlying tables partitioned is dropped/truncated/Merged/Moved. Local Partitioned Index Shares the same boundaries as the table and are in the same number as table partitions they are widely used in DSS and DWH systems. While Global Partitioned Index are predominantly used in OLTP systems
Views: 8831 Tech Coach
Oracle Partitioning
 
18:12
Oracle Partitioning watch more videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Parth Panjab, Tutorials Point India Private Limited
oracle date and time functions
 
21:33
Video from our Oracle SQL course. Check out the full course at.. http://learn.hackpress.co/courses/oracle-sql-learning-by-example
Views: 48309 etldeveloper
How to use partitioning to improve performance of large tables
 
42:49
In this video we cover in much more detail the improvement in performance that can be achieved by using partitioning. MS SQL server databases can scale well using this feature. We cover how partitioning a table gives similar performance as a single table with a clustered index, we then explore how adding NC index improve performance of the heap table as well as the partitioned table.
Views: 20415 Jayanth Kurup
Oracle Hints Tutorial for improving performance
 
10:35
Oracle Hints Tutorial for improving performance APPEND PARALLEL JOIN INDEX NO_INDEX SELECT /*+ FIRST_ROWS(10) */ * FROM emp WHERE deptno = 10; SELECT /*+ ALL_ROWS */ * FROM emp WHERE deptno = 10; SELECT /*+ NO_INDEX(emp emp_dept_idx) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; SELECT /*+ INDEX(e,emp_dept_idx) */ * FROM emp e WHERE e.deptno = 10; -- SELECT /*+ INDEX(scott.emp,emp_dept_idx) */ * FROM scott.emp; SELECT /*+ AND_EQUAL(e,emp_dept_idx) */ * FROM emp e; SELECT /*+ INDEX_JOIN(e,emp_dept_idx) */ * FROM emp e; SELECT /*+ PARALLEL_INDEX(e,emp_dept_idx , 8) */ * FROM emp e; SELECT /*+ LEADING (dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; SELECT /*+ PARALLEL(8) CACHE (e) FULL (e) */ * FROM emp e ; SELECT /*+ PARALLEL FULL (e) */ * FROM emp e ; SELECT /*+ PARALLEL USE_MERGE (emp dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; -- SORT Merge Join SELECT /*+ PARALLEL USE_HASH (emp dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; -- Hash Join SELECT /*+ PARALLEL */ * FROM emp e ; INSERT /*+ APPEND */ INTO mytmp select /*+ CACHE (e) */ *from emp e; commit;
Views: 10218 TechLake
Does partitioning Improve performance ? Explained
 
07:14
Partitioning is a great feature for improving the way we manage our data. However we can also improve performance of select statements from the table as well. This requires a good understanding of the way partitioning works and how properly placing files on the disk can improve the IO performance. One common way that partitioning can improve performance for loading data is the sliding window method but in this post I am mainly talking about how to improve read performance. Before showing the improvements from partitioning it’s important to visit the indexes since a common belief is that a good index can provide faster data access than partitioning can.
Views: 1284 Jayanth Kurup
Over clause in SQL Server
 
09:13
over partition by in sql server 2008 sql server over clause partition partition by clause in sql server 2008 over partition by clause in sql In this video we will discuss the power and use of Over clause in SQL Server. The OVER clause combined with PARTITION BY is used to break up data into partitions. Syntax : function (...) OVER (PARTITION BY col1, Col2, ...) The specified function operates for each partition. For example : COUNT(Gender) OVER (PARTITION BY Gender) will partition the data by GENDER i.e there will 2 partitions (Male and Female) and then the COUNT() function is applied over each partition. Any of the following functions can be used. Please note this is not the complete list. COUNT(), AVG(), SUM(), MIN(), MAX(), ROW_NUMBER(), RANK(), DENSE_RANK() etc. Example : SQl Script to create Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Gender nvarchar(10), Salary int ) Go Insert Into Employees Values (1, 'Mark', 'Male', 5000) Insert Into Employees Values (2, 'John', 'Male', 4500) Insert Into Employees Values (3, 'Pam', 'Female', 5500) Insert Into Employees Values (4, 'Sara', 'Female', 4000) Insert Into Employees Values (5, 'Todd', 'Male', 3500) Insert Into Employees Values (6, 'Mary', 'Female', 5000) Insert Into Employees Values (7, 'Ben', 'Male', 6500) Insert Into Employees Values (8, 'Jodi', 'Female', 7000) Insert Into Employees Values (9, 'Tom', 'Male', 5500) Insert Into Employees Values (10, 'Ron', 'Male', 5000) Go Write a query to retrieve total count of employees by Gender. Also in the result we want Average, Minimum and Maximum salary by Gender. This can be very easily achieved using a simple GROUP BY query as show below. SELECT Gender, COUNT(*) AS GenderTotal, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender What if we want non-aggregated values (like employee Name and Salary) in result set along with aggregated values You cannot include non-aggregated columns in the GROUP BY query. SELECT Name, Salary, Gender, COUNT(*) AS GenderTotal, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender The above query will result in the following error : Column 'Employees.Name' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause One way to achieve this is by including the aggregations in a subquery and then JOINING it with the main query as shown in the example below. Look at the amount of T-SQL code we have to write. SELECT Name, Salary, Employees.Gender, Genders.GenderTotals, Genders.AvgSal, Genders.MinSal, Genders.MaxSal FROM Employees INNER JOIN (SELECT Gender, COUNT(*) AS GenderTotals, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender) AS Genders ON Genders.Gender = Employees.Gender Better way of doing this is by using the OVER clause combined with PARTITION BY SELECT Name, Salary, Gender, COUNT(Gender) OVER(PARTITION BY Gender) AS GenderTotals, AVG(Salary) OVER(PARTITION BY Gender) AS AvgSal, MIN(Salary) OVER(PARTITION BY Gender) AS MinSal, MAX(Salary) OVER(PARTITION BY Gender) AS MaxSal FROM Employees Text version of the video http://csharp-video-tutorials.blogspot.com/2015/09/over-clause-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/09/over-clause-in-sql-server_29.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 95514 kudvenkat
Advanced SQL Queries in Oracle and SQL Server - What is PARTITION BY?
 
05:24
This video clip, on the PARTITION BY Clause used with analytic functions, is taken from my www.pluralsight.com course "Advanced SQL Queries in Oracle and SQL Server". Click here to learn more about this course: http://www.pluralsight.com/courses/adv-sql-queries-oracle-sql-server?utm_source=youtube&utm_medium=video&utm_campaign=authordemo.
Views: 5502 sheepsqueezersYT
02 How to configure Rang partition In oracle database
 
15:35
Now a days enterprises run databases of hundred of Gigabytes in size. These databases are known as Very Large Databases (VLDB). From Oracle Ver. 8.0 Oracle has provided the feature of table partitioning i.e. you can partition a table according to some criteria . For example you have a SALES table with the following structure Suppose this table contains millions of records, but all the records belong to four years only i.e. 1991, 1992, 1993 and 1994. And most of the time you are concerned about only one year i.e. you give queries like the following select sum(amt) from sales where year=1991; select product,sum(amt) from sales where year=1992 Group by product; Now whenever you give queries like this Oracle will search the whole table. If you partition this table according to year, then the performance is improve since oracle will scan only a single partition instead of whole table. This type of partitioning is useful when dealing with data that has logical ranges into which it can be distributed; for example, value of year. Performance is best when the data evenly distributes across the range
Views: 1952 Md Arshad
T-SQL: Over() and Partition By
 
04:17
Show how to use OVER and PARTITION BY to get groups of data with aggregation.
Views: 10165 MidnightDBA
How to Fetch Latest record/row from the Table in Oracle Database
 
03:32
You will learn how to How to Fetch Latest record/row from the Table in Oracle Database. Realtime Scenario: This logic can be implemented to find whether the latest record should be inserted or updated to datawarehouse
Hash Partition in Oracle
 
05:08
This course has been designed to impart the in-depth knowledge about the partitioning types and architecture in the Oracle RDBMS. For more information on this course, please visit https://www.koenig-solutions.com/oracle-database-12-c-implement-partitioning-training.aspx
Views: 106 Koenig Solutions
How to add Hard Disks in Oracle VirtualBox
 
02:53
We will learn how to add hard disks into an existing virtual machines. This is identical to adding hard disks to a physical machine and can be used for a variety of reasons: more data storage, better performance or increased reliability via RAID setup and others. Dynamic Storage Terms: http://www.avoiderrors.net/?p=4034
Views: 42012 AvoidErrors
Oracle SQL Tutorial 9 - Intro to Queries
 
04:55
This video is for beginners who have never worked with SQL Developer, and we are going to teach how to begin writing queries. So the queries we are going to start with are queries when we give the database an expression and it will return back some kind of value. The most common keyword you are going to need to know for Oracle is SELECT. SELECT is the command we use to get data from the database. Even though we have not really put any data in our database, we can still use the SELECT statement to get data. That's because the database is capable of doing more than just creating tables and retrieving data from tables. So our first goal is to essentially write a Hello World, which just displays the text hello world to us. A good place to start is with: SELECT 'Hello World' This would actually work for many database management systems, but when you run it you will get an error. This actually doesn't work with Oracle, it will tell us we always need the FROM keyword. To get around this, there is a magical table called DUAL. We can put anything we want to SELECT and then say FROM DUAL and it will work. SELECT 'Hello World' FROM DUAL We can also do math: SELECT 1+1 FROM DUAL And we can run even run functions: SELECT SYSTIMESTAMP FROM DUAL To put all of this together, you can grab all of this data at the same time using commas to separate different columns from our generated table: SELECT 'Hello World', 1+1, SYSTIMESTAMP FROM DUAL Support me on Patreon: http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 32885 Caleb Curry
Row Number function in SQL Server
 
07:24
sql server row_number example sql server row number by partition sql server row_number over partition by order by In this video we will discuss Row_Number function in SQL Server. This is continuation to Part 108. Please watch Part 108 from SQL Server tutorial before proceeding. Row_Number function Introduced in SQL Server 2005 Returns the sequential number of a row starting at 1 ORDER BY clause is required PARTITION BY clause is optional When the data is partitioned, row number is reset to 1 when the partition changes Syntax : ROW_NUMBER() OVER (ORDER BY Col1, Col2) Row_Number function without PARTITION BY : In this example, data is not partitioned, so ROW_NUMBER will provide a consecutive numbering for all the rows in the table based on the order of rows imposed by the ORDER BY clause. SELECT Name, Gender, Salary, ROW_NUMBER() OVER (ORDER BY Gender) AS RowNumber FROM Employees Please note : If ORDER BY clause is not specified you will get the following error The function 'ROW_NUMBER' must have an OVER clause with ORDER BY Row_Number function with PARTITION BY : In this example, data is partitioned by Gender, so ROW_NUMBER will provide a consecutive numbering only for the rows with in a parttion. When the partition changes the row number is reset to 1. SELECT Name, Gender, Salary, ROW_NUMBER() OVER (PARTITION BY Gender ORDER BY Gender) AS RowNumber FROM Employees Use case for Row_Number function : Deleting all duplicate rows except one from a sql server table. Discussed in detail in Part 4 of SQL Server Interview Questions and Answers video series. Text version of the video http://csharp-video-tutorials.blogspot.com/2015/09/rownumber-function-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/09/rownumber-function-in-sql-server_30.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 90262 kudvenkat
Oracle sql Interview Question : How to change rows to column
 
09:18
This video tutorial talks about the frequently asked oracle sql interview question of changing rows to the column. Based on the given scenario, we are asked to change the presentation of data in a table with 3 rows and 2 column to 3 columns and 2 rows. Decode Function in oracle https://youtu.be/YUAjPMjqMws Pivot and unpivot in oracle https://youtu.be/6s0DI1YcWIM
Views: 19272 Kishan Mashru
Difference between Row Number, Rank and Dense Rank | Oracle SQL Tutorial | Mr.Murali
 
20:46
►For Registration : https://goo.gl/r6kJbB ►Call: +91-8179191999 ► Visit Our Website: http://nareshit.in/ http://nareshit.com/ ► About NareshIT: "Naresh IT is the Best Software Training Institute for Hadoop, Salesforce, AWS, DevOps, Sprak, Data Science, Python, Tableau, RPA ,Java, C#.NET, ASP.NET, Oracle, Testing Tools, Silver light, Linq, SQL Server, Selenium, Android, iPhone, C Language, C++, PHP and Digital Marketing in Hyderabad, Chennai and Vijayawada, India which provides online and classroom training classes" ►For Registration : https://goo.gl/r6kJbB ►Call: India- 8179191999, USA- 404-232-9879 Email: [email protected] ►Our Online Training Features: 1.Training with Real-Time Experts 2.Industry Specific Scenario’s 3.Flexible Timings 4.Soft Copy of Material 5.Share Video's of each and every session. Check The Below Links: ►For Course Reg : https://goo.gl/r6kJbB ► Subscribe to Our Channel: https://goo.gl/q9ozyG ► Circle us on G+: https://plus.google.com/NareshIT ► Like us on Facebook: https://www.facebook.com/NareshIT ► Follow us on Twitter: https://twitter.com/nareshitech ► Visit Our Website: http://nareshit.in/ http://nareshit.com/
Views: 12362 Naresh i Technologies
SQL tutorial 62: Indexes In Oracle Database By Manish Sharma RebellionRider
 
04:03
Watch and learn concepts of SQL Index In Oracle Database. In this tutorial you will learn about B-Tree Index and Function based Index. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : Previous Tutorial ► ------------------------------------------------------------------------- ►►►Help Me In Getting A Job◄◄◄ ►Help Me In Getting A Good Job By Connecting With Me on My LinkedIn and Endorsing My Skills. All My Contact Info is Down Below. You Can Also Refer Me To Your Company Thanks ------------------------------------------------------------------------- Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=kb4rc1 -------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the 1st one to see my videos! -------------------------------------------------------------------------- Amazon Wishlist: http://bit.ly/wishlist-amazon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at for E-mail address please check About section Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 43340 Manish Sharma
ORACLE Analytic Functions for Data Warehousing 1/ Arabic
 
16:59
ORACLE Analytic Functions for Data Warehousing 1/ Arabic --analytic functions allow developers to perform tasks in SQL that were previously confined to procedural languages. -- let's start by aggregate functions ( sum, avg, count,...) select * from EMPLOYEES; select avg(salary) from employees; select DEPARTMENT_ID, avg(salary) from employees group by DEPARTMENT_ID order by 1 /* Analytic functions also operate on subsets of rows, similar to aggregate functions in GROUP BY queries, but they do not reduce the number of rows returned by the query */ select avg(salary) from employees; select employee_id, first_name,salary,(select avg(salary) from employees) avg_sal from EMPLOYEES; --analytic_function([ arguments ]) OVER (analytic_clause) --The analytic_clause breaks down into the following optional elements. --[ query_partition_clause ] [ order_by_clause [ windowing_clause ] ] select employee_id, first_name,salary, avg(salary) over() avg_sal from EMPLOYEES; select employee_id, first_name,salary, avg(salary) over( order by EMPLOYEE_ID ) from EMPLOYEES; select DEPARTMENT_ID, avg(salary) from employees group by DEPARTMENT_ID order by 1 select employee_id, first_name,salary,DEPARTMENT_ID, avg(salary) over(PARTITION BY DEPARTMENT_ID) avg_sal_dept from EMPLOYEES; select employee_id, first_name,salary,DEPARTMENT_ID, avg(salary) over(PARTITION BY DEPARTMENT_ID order by employee_id ) from EMPLOYEES drop table concan_card; create table concan_card ( rec_serial number primary key, game_name varchar2(100), game_round number, player_name varchar2(100), game_round_score number ); insert into concan_card values(1,'GAME1',1,'ahmed', -60); insert into concan_card values(2,'GAME1',1,'khaled', 200); insert into concan_card values(3,'GAME1',1,'ali', 30); insert into concan_card values(4,'GAME1',2,'ahmed', 10); insert into concan_card values(5,'GAME1',2,'khaled', -30); insert into concan_card values(6,'GAME1',2,'ali', 100); insert into concan_card values(7,'GAME1',3,'ahmed', -30); insert into concan_card values(8,'GAME1',3,'khaled', 100); insert into concan_card values(9,'GAME1',3,'ali', 6); select * from concan_card select rec_serial,game_name ,game_round,player_name, game_round_score, sum(game_round_score) over ( PARTITION BY player_name order by player_name,game_round ) from concan_card select rec_serial,game_name ,game_round,player_name, game_round_score, sum(game_round_score) over ( PARTITION BY player_name order by rec_serial ) from concan_card select rec_serial,game_name ,game_round,player_name, game_round_score, sum(game_round_score) over ( PARTITION BY game_name,player_name order by rec_serial ) from concan_card insert into concan_card values(10,'GAME2',1,'ahmed', -60); insert into concan_card values(11,'GAME2',1,'khaled', 200); insert into concan_card values(12,'GAME2',1,'ali', 30); insert into concan_card values(13,'GAME2',2,'ahmed', 10); insert into concan_card values(14,'GAME2',2,'khaled', -30); insert into concan_card values(15,'GAME2',2,'ali', 100); insert into concan_card values(16,'GAME2',3,'ahmed', -30); insert into concan_card values(17,'GAME2',3,'khaled', 100); insert into concan_card values(18,'GAME2',3,'ali', 6); select rec_serial,game_name ,game_round,player_name, game_round_score, sum(game_round_score) over ( PARTITION BY player_name order by player_name,game_round ) from concan_card select rec_serial,game_name ,game_round,player_name, game_round_score, sum(game_round_score) over ( PARTITION BY player_name order by rec_serial ) from concan_card select rec_serial,game_name ,game_round,player_name, game_round_score, sum(game_round_score) over ( PARTITION BY game_name,player_name order by rec_serial ) from concan_card
Views: 5614 khaled alkhudari
Part 4   Delete duplicate rows in sql
 
03:26
Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-4-delete-duplicate-rows-in-sql.html In this video, we will discuss deleting all duplicate rows except one from a sql server table. SQL Script to create Employees table Create table Employees ( ID int, FirstName nvarchar(50), LastName nvarchar(50), Gender nvarchar(50), Salary int ) GO Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) The delete query should delete all duplicate rows except one. Here is the SQL query that does the job. PARTITION BY divides the query result set into partitions. WITH EmployeesCTE AS ( SELECT *, ROW_NUMBER()OVER(PARTITION BY ID ORDER BY ID) AS RowNumber FROM Employees ) DELETE FROM EmployeesCTE WHERE RowNumber ] 1
Views: 365534 kudvenkat
Oracle Interview Questions: Dual table in Oracle
 
08:10
This video is the 2nd video in the video series Oracle Interview questions.It explains dual table in oracle along with the advantages that it offers. Below tutorial explains how you can generate test data in oracle using oracle table and hierarchical queries. https://www.youtube.com/watch?v=Lf8m9lXNPnc&t=25s
Views: 3422 Tech Coach
Oracle 11g Hints Overview
 
42:56
In this Video tutorial we will discuss about Optimizer hints in Oracle. What is optimizer hint, when & why its needed. Different Category of hints. Description of mostly used hints. Demonstrate how query plan can change with the influence of hint.
Views: 54153 Anindya Das
Query Analysis and Optimizing in Oracle
 
37:53
Database Management Systems 11. Query Analysis and Optimizing in Oracle ADUni
Views: 85355 Chao Xu
Rank and Dense Rank in SQL Server
 
10:08
rank and dense_rank example difference between rank and dense_rank with example rank vs dense_rank in sql server 2008 sql server difference between rank and dense_rank In this video we will discuss Rank and Dense_Rank functions in SQL Server Rank and Dense_Rank functions Introduced in SQL Server 2005 Returns a rank starting at 1 based on the ordering of rows imposed by the ORDER BY clause ORDER BY clause is required PARTITION BY clause is optional When the data is partitioned, rank is reset to 1 when the partition changes Difference between Rank and Dense_Rank functions Rank function skips ranking(s) if there is a tie where as Dense_Rank will not. For example : If you have 2 rows at rank 1 and you have 5 rows in total. RANK() returns - 1, 1, 3, 4, 5 DENSE_RANK returns - 1, 1, 2, 3, 4 Syntax : RANK() OVER (ORDER BY Col1, Col2, ...) DENSE_RANK() OVER (ORDER BY Col1, Col2, ...) RANK() and DENSE_RANK() functions without PARTITION BY clause : In this example, data is not partitioned, so RANK() function provides a consecutive numbering except when there is a tie. Rank 2 is skipped as there are 2 rows at rank 1. The third row gets rank 3. DENSE_RANK() on the other hand will not skip ranks if there is a tie. The first 2 rows get rank 1. Third row gets rank 2. SELECT Name, Salary, Gender, RANK() OVER (ORDER BY Salary DESC) AS [Rank], DENSE_RANK() OVER (ORDER BY Salary DESC) AS DenseRank FROM Employees RANK() and DENSE_RANK() functions with PARTITION BY clause : Notice when the partition changes from Female to Male Rank is reset to 1 SELECT Name, Salary, Gender, RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS [Rank], DENSE_RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS DenseRank FROM Employees Use case for RANK and DENSE_RANK functions : Both these functions can be used to find Nth highest salary. However, which function to use depends on what you want to do when there is a tie. Let me explain with an example. If there are 2 employees with the FIRST highest salary, there are 2 different business cases 1. If your business case is, not to produce any result for the SECOND highest salary, then use RANK function 2. If your business case is to return the next Salary after the tied rows as the SECOND highest Salary, then use DENSE_RANK function Since we have 2 Employees with the FIRST highest salary. Rank() function will not return any rows for the SECOND highest Salary. WITH Result AS ( SELECT Salary, RANK() OVER (ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 2 Though we have 2 Employees with the FIRST highest salary. Dense_Rank() function returns, the next Salary after the tied rows as the SECOND highest Salary WITH Result AS ( SELECT Salary, DENSE_RANK() OVER (ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 2 You can also use RANK and DENSE_RANK functions to find the Nth highest Salary among Male or Female employee groups. The following query finds the 3rd highest salary amount paid among the Female employees group WITH Result AS ( SELECT Salary, Gender, DENSE_RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 3 AND Gender = 'Female' Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/rank-and-denserank-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/rank-and-denserank-in-sql-server_1.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 84073 kudvenkat
ORACLE Analytic Functions for Data Warehousing 2/ Arabic
 
12:32
ORACLE Analytic Functions for Data Warehousing 2/ Arabic FIRST_VALUE last_VALUE row_number() --FIRST_VALUE and LAST_VALUE Analytic Functions select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE from employees order by hire_date; select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , min(HIRE_DATE) over ( ) first_HIRE_DATE from employees select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , FIRST_VALUE(HIRE_DATE) over ( ) first_HIRE_DATE from employees order by hire_date; select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , max(HIRE_DATE ) over ( ) last_HIRE_DATE from employees select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , last_VALUE(HIRE_DATE ) over ( ) last_HIRE_DATE from employees order by HIRE_DATE drop table student_exam_result; CREATE TABLE student_exam_result (student_id number, exame_name varchar2(100), exame_try number, exame_results number ); insert into student_exam_result values(1,'calcluas',1,50); insert into student_exam_result values(1,'calcluas',2,66); insert into student_exam_result values(1,'calcluas',3,20); insert into student_exam_result values(2,'calcluas',1,66); insert into student_exam_result values(2,'calcluas',2,null); insert into student_exam_result values(2,'calcluas',3,7); insert into student_exam_result values(3,'calcluas',1,50); insert into student_exam_result values(3,'calcluas',2,98); insert into student_exam_result values(3,'calcluas',3,null); select * from student_exam_result select student_id, exame_name,exame_try,exame_results, last_value(exame_results) IGNORE NULLS over (PARTITION BY student_id, exame_name ) last_grade from student_exam_result order by student_id, exame_name, exame_try select student_id, exame_name,exame_try,exame_results, last_value(exame_results) IGNORE NULLS over (PARTITION BY student_id, exame_name ) last_grade, max(exame_results) over (PARTITION BY student_id, exame_name ) max_grade, avg(exame_results) over (PARTITION BY student_id, exame_name ) avg_grade from student_exam_result order by student_id, exame_name, exame_try ------------------------ select employee_id,first_name ,row_number() over(order by employee_id ) from employees select employee_id,first_name ,rownum from employees select employee_id,first_name ,department_id, row_number() over(partition by department_id order by employee_id ) from employees
Views: 791 khaled alkhudari
How to view table structure in oracle database .
 
00:28
How to view table structure in oracle database .
Views: 480 latest ITChannel
SQL: Group By,  Having, Min, Max Sum
 
14:43
Learn to summarize yoru data using the SQL Aggregates such as count and sum and the GROUP BY and HAVING clauses of the SELECT statement
Views: 158870 Michael Fudge
[HowTo] CentOS / RHEL 7 Installation with Custom Partitioning [www.tejasbarot.com]
 
22:02
RHEL 7 / CentOS 7 Installation Video. This Video will show you How to Install CentOS Operating System with Custom Paritioning, Please do not forget to give feedback on www.tejasbarot.com, Keep Visiting Blog.
Views: 44216 Tejas Barot
Learn Oracle | How to use the Merge Statement in SQL
 
04:13
Pebbles present, Learn Oracle 10g with Step By Step Video Tutorials. Learn Oracle 10g Tutorial series contains the following videos : Learn Oracle - History of Oracle Learn Oracle - What is Oracle - Why do we need Oracle Learn Oracle - What is a Database Learn Oracle - What is Grid Computing Learn Oracle - What is Normalization Learn Oracle - What is ORDBMS Learn Oracle - What is RDBMS Learn Oracle - Alias Names, Concatenation, Distinct Keyword Learn Oracle - Controlling and Managing User Access (Data Control Language) Learn Oracle - Introduction to SQL Learn Oracle - Oracle 10g New Data Types Learn Oracle - How to Alter a Table using SQL Learn Oracle - How to Create a Package in PL SQL Learn Oracle - How to Create a Report in SQL Plus Learn Oracle - How to Create a Table using SQL - Not Null, Unique Key, Primary Key Learn Oracle - How to Create a Table using SQL Learn Oracle - How to Create a Trigger in PL SQL Learn Oracle - How to Delete Data from a Table using SQL Learn Oracle - How to Drop and Truncate a Table using SQL Learn Oracle - How to Insert Data in a Table using SQL Learn Oracle - How to open ISQL Plus for the first time Learn Oracle - How to Open SQL Plus for the First Time Learn Oracle - How to Update a Table using SQL Learn Oracle - How to use Aggregate Functions in SQL Learn Oracle - How to use Functions in PL SQL Learn Oracle - How to use Group By, Having Clause in SQL Learn Oracle - How to Use Joins, Cross Join, Cartesian Product in SQL Learn Oracle - How to use Outer Joins (Left, Right, Full) in SQL Learn Oracle - How to use the Character Functions, Date Functions in SQL Learn Oracle - How to use the Merge Statement in SQL Learn Oracle - How to use the ORDER BY Clause with the Select Statement Learn Oracle - How to use the SELECT Statement Learn Oracle - How to use the Transactional Control Statements in SQL Learn Oracle - How to use PL SQL Learn Oracle - Data Types in PL SQL Learn Oracle - Exception Handling in PL SQL Learn Oracle - PL SQL Conditional Logics Learn Oracle - PL SQL Cursor Types - Explicit Cursor, Implicit Cursor Learn Oracle - PL SQL Loops Learn Oracle - Procedure Creation in PL SQL Learn Oracle - Select Statement with WHERE Cause Learn Oracle - SQL Operators and their Precedence Learn Oracle - Using Case Function, Decode Function in SQL Learn Oracle - Using Logical Operators in the WHERE Clause of the Select Statement Learn Oracle - Using Rollup Function, Cube Function Learn Oracle - Using Set Operators in SQL Learn Oracle - What are the Different SQL Data Types Learn Oracle - What are the different types of Databases Visit Pebbles Official Website - http://www.pebbles.in Subscribe to our Channel – https://www.youtube.com/channel/UCNNjWVsQqaMYccY044vtHJw?sub_confirmation=1 Engage with us on Facebook at https://www.facebook.com/PebblesChennai Please Like, Share, Comment & Subscribe
Views: 1891 Pebbles Tutorials
SQL query to find first record and last record in single query
 
08:55
SQL query to find first record and last record in single query
Views: 11415 SQL Guru
HOW TO IDENTIFY AND DELETE DUPLICATE ROWS USING ROWID AND GROUPBY IN ORACLE SQL
 
07:53
This video demonstrates examples on how to find and delete duplicate records from a table. The video gives simple and easy to understand examples on finding duplicate records from a table using group by and having clause and row_number function. It also shows the ways in which duplicates can be deleted very efficiently using the rowid of that record. You can get the code from our website http://oracleplsqlblog.com/FullBlog/FullBlog/21
Views: 11869 Kishan Mashru
Oracle Database 12c: Enhanced Optimizer Statistics with Tom Kyte
 
09:11
Tom Kyte discusses enhanced optimizer statistics followed by a demo of on-load statistics gathering in Oracle Database 12c. "Online Statistics Gathering for Bulk Loads" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL344 "Histograms" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL366 "CREATE TABLE ... AS SELECT" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=DWHSG8317 "CREATE TABLE" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=SQLRF01402
Views: 8424 OracleDBVision
PL/SQL tutorial 67: PL/SQL Ref Cursors In Oracle Database by Manish Sharma
 
04:33
RebellionRider.com presents introduction to PL/SQL Ref Cursors / Cursor Variable in Oracle Database by Manish Sharma ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog: http://bit.ly/ref-cursor-1 Previous Tutorial ►Database Cursor (Playlist): http://bit.ly/2x0JGXz ► Record Datatype (Playlist): http://bit.ly/2xkcHOr ------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the 1st one to see my videos! ------------------------------------------------------------------------- ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ ___Facebook Official Page of Manish Sharma___ https://www.facebook.com/TheRebellionRider/ ___Facebook Official Page of RebellionRider.com___ https://www.facebook.com/RebellionRider.official/ You can also Email me at for E-mail address please check the About section Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 16844 Manish Sharma
Leaner, Faster Code with Advanced SQL Techniques
 
45:45
Connor Mcdonald, Developer Advocate for SQL, Oracle Most SQL is so simple to write that we can hand off the job to an ORM tool or a similar mechanism. But by delving a little deeper into more-advanced SQL facilities, we can get performance benefits and write a lot less middle-tier code. This session highlights some SQL techniques for solving problems that would otherwise require a lot of complex coding. Learn how to become a more productive developer by expanding your knowledge of the SQL language.
Views: 8140 Oracle Developers
Oracle Database System Tables and Selected Relevant Columns
 
27:17
Oracle Database System Tables and Selected Relevant Columns
Views: 163 Kiran Shahi
SQL tutorial 50: CASE - Searched Case Expression In Oracle (2/2)
 
05:52
Case expression let you perform IF-THEN-ELSE in oracle database. There are two type of case in oracle simple case expression and searched case expression. This SQL Tutorial 49 is about Simple Case Expression. ●Intro Of searched Case expression ● Syntax of SearchedCase Expression ● Query 1. Searched Case expression With logical operator using 2 columns ● Query 2. Searched Case Expression with Comparison operators and BETWEEN and IN operators. Celebrating 1000 subscribers. Thanks a lot guys for all your love and support. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog: ------------------------------------------------------------------------- Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=kb4rc1 -------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the first one to see my videos! -------------------------------------------------------------------------- Amazon Wishlist: http://bit.ly/wishlist-amazon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at [email protected] Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 28417 Manish Sharma
Combined use ORDER BY and PARTITION BY clauses together in Oracle SQL
 
03:20
In this video tutorial we will learn piecing the ORDER BY and PARTITION BY clauses in Oracle SQL
Views: 70 Spod ssppoodd
SQL tutorial 51: DECODE function in Oracle Database By Manish Sharma (RebellionRider)
 
05:04
SQL Tutorial 51 Decode function in Oracle Database. ● What Is DECODE() ● DECODE ( ) vs CASE ● Syntax of DECODE() ● Query 1. String Matching using DECODE() ● Query 2. DECODE() comparing values form the COLUMN of the table Celebrating 1000 subscribers. Thanks a lot guys for all your love and support. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog: ------------------------------------------------------------------------- Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=kb4rc1 -------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the first one to see my videos! -------------------------------------------------------------------------- Amazon Wishlist: http://bit.ly/wishlist-amazon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at [email protected] Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 36469 Manish Sharma
SQL: Rank & Dense_rank functions
 
06:47
In this tutorial, you'll learn the difference between rank() and dense_rank() functions..
Views: 28956 radhikaravikumar
Optimizing SQL Performance
 
51:42
Held on July 12 2018 In July's session we mainly looked at performance. Highlights include: 1:30 How does the database process subqueries? 5:20 Performance: comparing insert ... select to create tmp table, insert select from tmp; DDL in PL/SQL; dynamic SQL problems 12:45 18c private temporary tables; tables specific to a session; DDL you can rollback across! 21:00 Improving update performance: things to watch for; insert vs. update; "join-update" - create a view instead; create table as select "update" 34:05 Analytic function performance: first_value non-determinism; min keep vs first_value; computing function in a subquery; indexes for analytic functions AskTOM Office Hours offers free, monthly training and tips on how to make the most of Oracle Database, from Oracle product managers, developers and evangelists. https://asktom.oracle.com/ Oracle Developers portal: https://developer.oracle.com/ Sign up for an Oracle Cloud trial: https://cloud.oracle.com/en_US/tryit music: bensound.com
Views: 735 Oracle Developers
ORDER BY Clause in Oracle | Oracle Tutorials for Beginners
 
04:37
Oracle Tutorials for Beginners ORDER BY Clause In Oracle ORDER BY Clause in SQL Oracle Tutorials for Beginners Oracle SQL Introduction #Oracle Tutorisla for Beginners Oracle for Beginners Oracle plsql tutorial for Beginners Oracle plsql tutorial for Beginners Oracle plsql tutorial for Beginners ORDER BY in Oracle SQL ORDER BY in Oracle SQL ORDER BY in Oracle SQL NULLS FIRST in Oracle NULLS FIRST in Oracle NULLS LAST in Oracle NULLS LAST in Order by Clause how order by clause works in oracle oracle order by date oracle sort varchar2 alphabetically oracle order by case multiple columns oracle sql order by specific values order by in oracle w3schools sql order by multiple columns oracle order by column not in select order by in oracle w3schools oracle order by multiple columns oracle sql order by specific values how order by clause works in oracle oracle order by date oracle order by group by sql order by alphabetical order by sql
Views: 637 Oracle PL/SQL World
Oracle Database11g tutorials 11: SQL case manipulation function in Oracle Database
 
04:38
Part 2 SQL functions- character function -case manipulation functions Previous Video Link :: http://youtu.be/5rx8Q4x4-qI Tool used in this tutorial is command prompt. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for linking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ------------------------------------------------------------------------------------- As discuss in last video we have 3 case manipulation functions. In case you miss the SQL functions intro video you can find the link in the description below. First let's see what these functions are. Upper (): This function takes a parameter converts it into uppercase and returns the new string. Initcap (): this function also takes parameter and converts the initial letter of or parameter into uppercase and returns the new string. Lower (): This function takes a parameter converts it into lowercase and returns the new string. Ok let's do some practical For this practical we will be using 2 tables First is dual table Which is a dummy table provided by oracle? And I have created another table again by the name of example. This will be our second table. Let's start with SQL function upper ( ); SELECT upper('hello world') FROM dual; As you can see I have used "hello world" completely in lowercase as parameter to SQL upper function. Execute it. Here, our result has given us a completely new hello world string which is in uppercase. Similarly you can also use SQL upper function to perform other DML Let's try This time we will work on our second table EXAMPLE; insert into example values (upper('manish')); first parentheses for values and second for SQL function upper. Let's check the result. As you can see here inserted value is in upper case. Lets compare it with simple insert query Insert into example values ('manish'); Execute it, i think now it's clear that when we perform simple insert DML the inserted value will be the same you provide. Similarly let's try SQL function initcap(); SELECT initcap('hello world') FROM dual; As you see here in result the initial letters of string hello world are in uppercase. Let's do the insert query insert into example values (initcap('hello world')); initial letters of string also are in uppercase. Let's try SQL function lower(); This time we have to write our hello world in all caps. SELECT lower('HELLO WORLD') FROM dual; Execute String totally in lower case. Similarly you can user SQL function lower in other DML like insert and all.
Views: 89529 Manish Sharma
Window functions in SQL Server
 
11:00
sql server window function example window function sql server example sql server rows range clause sql server rows between 1 preceding and 1 following In this video we will discuss window functions in SQL Server In SQL Server we have different categories of window functions Aggregate functions - AVG, SUM, COUNT, MIN, MAX etc.. Ranking functions - RANK, DENSE_RANK, ROW_NUMBER etc.. Analytic functions - LEAD, LAG, FIRST_VALUE, LAST_VALUE etc... OVER Clause defines the partitioning and ordering of a rows (i.e a window) for the above functions to operate on. Hence these functions are called window functions. The OVER clause accepts the following three arguments to define a window for these functions to operate on. ORDER BY : Defines the logical order of the rows PARTITION BY : Divides the query result set into partitions. The window function is applied to each partition separately. ROWSor RANGE clause : Further limits the rows within the partition by specifying start and end points within the partition. The default for ROWS or RANGE clause is RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW Let us understand the use of ROWS or RANGE clause with an example. Compute average salary and display it against every employee We might think the following query would do the job. SELECT Name, Gender, Salary, AVG(Salary) OVER(ORDER BY Salary) AS Average FROM Employees As you can see from the result, the above query does not produce the overall salary average. It produces the average of the current row and the rows preceeding the current row. This is because, the default value of ROWS or RANGE clause (RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) is applied. To fix this, provide an explicit value for ROWS or RANGE clause as shown below. ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING tells the window function to operate on the set of rows starting from the first row in the partition to the last row in the partition. SELECT Name, Gender, Salary, AVG(Salary) OVER(ORDER BY Salary ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS Average FROM Employees The same result can also be achieved by using RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING Well, what is the difference between ROWS and RANGE We will discuss this in a later video The following query can be used if you want to compute the average salary of 1. The current row 2. One row PRECEDING the current row and 3. One row FOLLOWING the current row SELECT Name, Gender, Salary, AVG(Salary) OVER(ORDER BY Salary ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS Average FROM Employees Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/window-functions-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/window-functions-in-sql-server_7.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 65753 kudvenkat
Data Dictionary Views - Oracle SQL Developer
 
12:35
Query the dictionary views to find information about objects in your schema
Views: 903 MrFphunter
WITH Clause : PL/SQL Declaration Section in Oracle Database 12c
 
03:59
An explanation of how to use the PL/SQL declaration section in the WITH clause in Oracle Database 12c. For more information see: https://oracle-base.com/articles/12c/with-clause-enhancements-12cr1 Website: https://oracle-base.com Blog: https://oracle-base.com/blog Twitter: https://twitter.com/oraclebase Cameo by Chris Muir Blog: https://blogs.oracle.com/onesizedoesntfitall/ Twitter: https://twitter.com/chriscmuir Cameo appearances are for fun, not an endorsement of the content of this video.
Views: 17015 ORACLE-BASE.com