calling scalar function to assign value to local variable

Question

In a SQL Server stored procedure, if we declare a local variable and assign the value by calling a scalar function DECLARE @variable_name INT= dbo.scalarfuntion_name(@p1, @p2). Would it have any impact on overall performance of SP as in general using scalar function directly into script has performance downgrade most of the times? Thanks!

Answer 1

Two big problems with using functions in a query are that cardinalities are not accurate and that the function code is called once per row. When setting a variable neither of these are a concern. So I would think, generally speaking, there would be no measurable performance impact.

• Sunny: OK..Thanks Michael!