SQL Server Arithmetic Operators (-)

(-) subtraction operator is used to subtract two numbers, also subtracts a number from date as number of days.

DECLARE @someNumber int; SET @someNumber = 191;
SELECT '200' - @someNumber;

Result = 9 

DECLARE @initialdate datetime, @someNumber int;
SET @initialdate = ''June 26, 1982 07:33 AM';
SET @someNumber = 3;
SELECT @initialdate - @someNumber AS 'Final Date';
Result = 1982-06-23 07:33:00.000