这个存储过程为什么一调用就出错？

[boyandgirl222]

if exists(select name from sysobjects where type = 'P'and name = 'my')
drop proc my
go
create proc my
@a1 varchar(22) ,@a2 varchar(22)
as
begin
return @a1 +@a2
end
go
declare @aa varchar(22)
declare @bb varchar(22)
declare @cc varchar(22)
set @aa='3 '
set @bb='jjj'
exec @cc = my @aa ,@bb
print @cc

[filebat]

返回值只能是整数, 所以它自动会将@a1+@a2转化成整形.
但是'3 jjj'不可能转化成整型,所以就会出错.

你这种情况应该用output的输出参数,而不是返回值.
例如:
if object_id('my') is not null drop proc my
go
create proc my(@a1 varchar(22) ,@a2 varchar(22),
@ret varchar(44) output )
as
begin
set @ret=@a1+@a2
end
go
declare @aa varchar(22),@bb varchar(22),@cc varchar(22)
select @aa='3 ',@bb='jjj'
exec my @aa ,@bb, @cc output
print @cc

[vivianfdlpw]

存储过程返回值只能是int类型，你的情况需要用输出参数：

if exists(select name from sysobjects where type = 'P'and name = 'my')
drop proc my
go
create proc my
@a1 varchar(22) ,@a2 varchar(22),@a3 varchar(50) out
as
begin
set @a3=@a1 +@a2
end
go

declare @aa varchar(22)
declare @bb varchar(22)
declare @cc varchar(22)
set @aa='3 '
set @bb='jjj'
exec my @aa ,@bb,@cc out
print @cc

[tommysun]

if exists(select name from sysobjects where type = 'P'and name = 'my')
drop proc my
go
create proc my
@a1 varchar(22) ,@a2 varchar(22),@a3 varchar(44) output
as
begin
Select @a3 = @a1 +@a2

end
go
declare @aa varchar(22)
declare @bb varchar(22)
declare @cc varchar(44)
set @aa='3 '
set @bb='jjj'
execute my @aa ,@bb, @cc output
print @cc

[chenqianlong]

exec @cc = my @aa ,@bb出錯！
樓上正解。

[xzq111]

return <integer_expression>
你的存储过程错了