When you do an EXISTS on an aggregate, it's always going to be true. It returns a value even if the ID doesn't exist. Sure, it's NULL, but its returning it. Instead, do this: if exists(select 1 from table where id = 4) and you'll get to the ELSE portion of your IF statement.

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 tblGLUser...

The EXISTS operator is used to test for the existence of any record in a subquery. The EXISTS operator returns TRUE if the subquery returns one or more records. EXISTS Syntax

2010年11月23日 · WHERE [NOT] EXISTS ( SELECT 1 FROM MyTable WHERE ... ) This will be more efficient than SELECT * since you're simply selecting the value 1 for each row, rather than all the fields. There's also a subtle difference between COUNT(*) and COUNT(column name): COUNT(*) will count all rows, including nulls

2022年3月21日 · The IF EXISTS decision structure will execute a block of SQL code only if an inner query returns one or more rows. If the inner query returns an empty result set, the block of code within the structure is skipped.

2020年3月3日 · This article walks through different versions of the T-SQL IF EXISTS statement for the SQL database using various examples. IF EXISTS in SQL 2014 or before DROP ..IF EXISTS in SQL Server 2016 to SQL Server 2019

2024年11月22日 · Returns TRUE if a subquery contains any rows. A. Using NULL in a subquery to still return a result set. The following example returns a result set with NULL specified in the subquery and still evaluates to TRUE by using EXISTS. WHERE EXISTS (SELECT NULL) . ORDER BY Name ASC ; .

2024年12月17日 · IF EXISTS(SELECT * FROM sys.databases WHERE name = 'master') PRINT 'EXISTS evaluated to true' ELSE PRINT 'EXISTS evaluated to false' This is an example of EXISTS with a query that returns 0 rows. It is a perfectly valid …

The EXISTS operator allows you to check if a subquery returns any row. The EXISTS operator returns true if the subquery returns at least one row or false otherwise. Here’s the syntax of the EXISTS operator: SELECT column1, column2 FROM table_name WHERE EXISTS (subquery); Code language: SQL (Structured Query Language) (sql) In this syntax:

2024年12月10日 · It’s commonly used in scenarios where you need to check if a record exists in a related table, and you want to perform an action based on that result. Syntax: SELECT column_name(s) FROM subquery_table. WHERE condition. EXISTS: The boolean operator that checks if a subquery returns rows.