如何从存储过程返回字符串值

Alter procedure S_Comp(@str1 varchar(20),@r varchar(100) out)
as
declare  @str2 varchar(100)
set @str2  ='welcome to sql server. Sql server is a product of Microsoft'
if(PATINDEX('%'+@str1 +'%',@str2)>0)
    return @str1+'present in the string'
else 
    return @str1+'not present'
Alter procedure S_Comp(@str1 varchar(20),@r var