sql - What is SELF JOIN and when would you use it? - Stack Overflow
Jun 13, 2024 · You use a self join when a table references data in itself. E.g., an Employee table may have a SupervisorID column that points to the employee that is the boss of the current employee. To …
sql - NOT IN vs NOT EXISTS - Stack Overflow
Which of these queries is the faster? NOT EXISTS: SELECT ProductID, ProductName FROM Northwind..Products p WHERE NOT EXISTS ( SELECT 1 FROM Northwind..[Order Details] od …
CASE .. WHEN expression in Oracle SQL - Stack Overflow
CASE .. WHEN expression in Oracle SQL Asked 13 years, 2 months ago Modified 4 years, 9 months ago Viewed 968k times
SQL WITH clause example - Stack Overflow
Sep 23, 2012 · 353 The SQL WITH clause was introduced by Oracle in the Oracle 9i release 2 database. The SQL WITH clause allows you to give a sub-query block a name (a process also called …
Nested select statement in SQL Server - Stack Overflow
Check for more subquery rules and subquery types. More examples of Nested Subqueries. IN / NOT IN – This operator takes the output of the inner query after the inner query gets executed which can be …
sql - Case in Select Statement - Stack Overflow
Jan 7, 2013 · The following examples uses the CASE expression in an ORDER BY clause to determine the sort order of the rows based on a given column value. In the first example, the value in the …
How do I perform an IF...THEN in an SQL SELECT?
Sep 15, 2008 · 116 You can find some nice examples in The Power of SQL CASE Statements, and I think the statement that you can use will be something like this (from 4guysfromrolla):
Convert Rows to columns using 'Pivot' in SQL Server
Apr 10, 2013 · Pivot is one of the SQL operator which is used to turn the unique data from one column into multiple column in the output. This is also mean by transforming the rows into columns (rotating …
sql - Oracle "Partition By" Keyword - Stack Overflow
Oct 28, 2016 · Can someone please explain what the partition by keyword does and give a simple example of it in action, as well as why one would want to use it? I have a SQL query written by …
SQL Case Expression Syntax? - Stack Overflow
Aug 7, 2008 · Search conditions are detailed in the Transact-SQL User’s Guide. then precedes the expression that specifies a result value of case. expression is a column name, a constant, a function, …