-= (Subtract EQUALS) (Transact-SQL)
Applies To: SQL Server 2014, SQL Server 2016 Preview
Topic Status: Some information in this topic is preview and subject to change in future releases. Preview information describes new features or changes to existing features in Microsoft SQL Server 2016 Community Technology Preview 2 (CTP2).
Subtracts two numbers and sets a value to the result of the operation. For example, if a variable @x equals 35, then @x -= 2 takes the original value of @x, subtracts 2 and sets @x to that new value (33).
Applies to: SQL Server (SQL Server 2008 through current version), Azure SQL Database.
Returns the data type of the argument with the higher precedence. For more information, see Data Type Precedence (Transact-SQL).