Apply function to the result of a select

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Apply function to the result of a select

nano2nd

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April 8, 2010 at 7:55 am

#221119

Suppose I have a function that performs some mathematical operation on the input parameter x and returns a value y:
select dbo.MyMathFunc(10)
Is there a way to apply the function to the results of a select such as:
select dbo.MyMathFunc(select MyInt from MyTable)
Maybe I just can't come up with the correct syntax.

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Lynn Pettis SSC Guru Points: 442467 More actions · Answer 1

nano2nd (4/8/2010)
Suppose I have a function that performs some mathematical operation on the input parameter x and returns a value y:
select dbo.MyMathFunc(10)
Is there a way to apply the function to the results of a select such as:
select dbo.MyMathFunc(select MyInt from MyTable)
Maybe I just can't come up with the correct syntax.

This?

declare @MyVariable as int;

select @MyVariable = MyInt from dbo.MyTable; -- where this returns one row or the last value from multiple rows

select dbo.MyMathFunc(@MyVariable);

nano2nd Hall of Fame Points: 3073 More actions · Answer 2

Thanks, it worked as you expected. It applies the function to the first row returned from the select. How do I apply it iteratively to each of the rows in the table?

Lynn Pettis SSC Guru Points: 442467 More actions · Answer 3

nano2nd (4/8/2010)
Thanks, it worked as you expected. It applies the function to the first row returned from the select. How do I apply it iteratively to each of the rows in the table?

That is what you asked for initially. Try this:

select dbo.MyMathFunc(MyInt) from dbo.MyTable;

nano2nd Hall of Fame Points: 3073 More actions · Answer 4

Thanks, that did it. I really appreciate the help.