Tuesday, November 27, 2007

Integer Math In SQL Server

What do you think the following query will return in SQL Server?

SELECT 3/2

If you said 1.5 then you are wrong! The correct answer is 1, this is because when doing division with 2 integers the result will also be an integer.
There are two things you can do
1 multiply one of the integers by 1.0
2 convert one of the integers to a decimal


Integer math is integer result
DECLARE @Val1 INT,@val2 INT
SELECT @Val1 =3, @val2 =2

SELECT @Val1/@Val2
Result 1

Convert explicit or implicit to get the correct answer
DECLARE @Val1 INT,@val2 INT
SELECT @Val1 =3, @val2 =2

--Implicit
SELECT @Val1/(@Val2*1.0)
--Explicit
SELECT CONVERT(DECIMAL(18,4),@Val1)/@Val2

Result 1.50000000000000

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