What is wrong with this SQL Server query division calculation?

Question

I have this table structure on a SQL Server 2008 R2 database:

  CREATE TABLE FormTest
(   
clientid char(10),
DateSelected date,
A int,
B int,
C int
)


        

Answer 1

It's because you are doing integer division. You should convert one of the operands to float, or decimal (depending on the precision and purpose of the calculation you are doing), using something like:

((CAST((a+ b + c) AS FLOAT) / 3) / 216647 * 10)

or possibly:

(((a+ b + c) / 3.0) / 216647.0 * 10)

Answer 2

declare @a int
declare @b int
declare @c int
set @a=65150
set @b=4921
set @c=1

select convert(float,((@a+@b+@c)/ 216647.0 * 10) )

Answer 3

You're performing integer arithmetic, so your results will always be rounded down to the nearest whole number. Since you're dividing by 3, then by 216647, based on the numeric inputs your result is getting rounded down to 0 every time. You'll need to use either a decimal (exact) or floating point (approximate) data type and/or casting if you want to get non-integer results.

Answer 4

Dividing integers will result in an integer (The remainder part will be ignored). Hence, when dividing, work with decimals or floats. This should work in addition to the float solutions given earlier. Replace (12,2) with your preferred precision:

SELECT clientid, (((
Cast(a as decimal(12,2)) + 
Cast(b as decimal(12,2)) + 
Cast(c as decimal(12,2)) 
) / 3) / 216647 * 10) AS Formula1 
FROM FormTest