- (Subtract) (T-SQL)

Subtracts two numbers. This substraction arithmetic operator can also subtract a number, in days, from a date.

Syntax

expression - expression

Arguments

expression

Is any valid Microsoft® SQL Server™ expression of any of the data types of the numeric data type category except the bit data type.

Result Types

Returns the data type of the argument with the higher precedence. For more information, see Data Type Precedence.

Examples

A. Use subtraction in a SELECT statement

This example returns the amount of the year-to-date revenues retained by the company for each book title.

USE pubs

GO

SELECT title,

    (

        (price * ytd_sales) * CAST( ( (100 - royalty) / 100.0 )

            AS MONEY)

        ) AS IncomeAfterRoyalty

FROM titles

WHERE royalty <> 0

ORDER BY title_id ASC

GO

Parentheses can be used to change the order of execution. Calculations inside parentheses are evaluated first. If parentheses are nested, the most deeply nested calculation has precedence. For example, the result and meaning of the preceding query can be changed if you use parentheses to force the evaluation of subtraction before multiplication, which in this case would yield a meaningless number.

B. Use date subtraction

This example subtracts a number of days from a datetime date.

USE pubs

GO

DECLARE @altstartdate datetime

SET @altstartdate = '1/10/1900 3:00 AM'

SELECT @altstartdate - 1.5 AS 'Subtract Date'

Here is the result set:

Subtract Date              

--------------------

Jan 8 1900  3:00PM         

(1 row(s) affected)

See Also