Using the exists operator, your subquery can return zero, one, or many rows, and the condition simply checks whether the subquery returned any rows. If you look at the select clause of the subquery, you …

Aug 24, 2008 · What is the difference between the EXISTS and IN clause in SQL? When should we use EXISTS, and when should we use IN?

Nov 23, 2010 · For example if you want to check if user exists before inserting it into the database the query can look like this:

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 …

SQL Server: IF EXISTS ; ELSE Asked 14 years, 2 months ago Modified 6 years, 2 months ago Viewed 745k times

Using Sql Server 2012. I have a stored procedure and part of it checks if a username is in a table. If it is, return a 1, if not, return a 2. This is my code: IF EXISTS (SELECT * FROM tblGLUserA...

How to select Boolean value from sub query with IF EXISTS statement (SQL Server)? It should be something like : SELECT TABLE1.Id, NewFiled = (IF EXISTS (SELECT Id FROM TABLE2 WHERE …

Dec 29, 2016 · Products like SQL Server, Oracle, MySQL and SQLite will happily accept SELECT * in the above query without any errors, which probably means they treat an EXISTS SELECT in a …

Jul 27, 2011 · Several possible SQL statements given as solutions. IMPORTANT NOTE: the statements that JOIN the other tables in the outer query have the potential to return "duplicate" rows (unless we …

Please note that EXISTS with an outer reference is a join, not just a clause. It is a semi-join (and NOT EXISTS is an anti-semi-join). Also, you can use EXISTS to join tables, one example being Customer …