The custom function of the SQL Server bug set and the group by

server| function
/**==** 1. The custom function was used for group by error **==**/--a simple function Create functions f_str (@str sysname,@i int) returns char (1) as Begin return (SUBSTRING (@ str,@i,1)) Endgo

--Here's the test

--Define test data declare @t table (name sysname) insert into @t values (' ABCD ')

--a case of group by, resulting in error select A=DBO.F_STR (name,1), B=dbo.f_str (name,2) from @tgroup by Dbo.f_str (name,1), Dbo.f_str (name,2 )

-Without group BY, the result is correct select A=DBO.F_STR (name,1), B=dbo.f_str (name,2) from @tgo

--Deletes the custom function of the test drop function f_str

/*--Test Results A b--------a A

(The number of rows affected is 1 rows)

A b--------a b

(The number of rows affected is 1 rows)--*/