Question

I want to return a varchar(max) from a stored procedure in SQL Server 2008.

So I tried:

alter proc SpSignup(
    @username varchar(max),
    @email varchar(max),
    @password varchar(max),
    @warning varchar(max) output)
as
   if exists(select email from [login] where email=@email)
      return 'email already exists';

   insert into [login](username, email, password) 
   values(@username, @email, @password)

I want to return a varchar value ('email already exists') if the email exists in the table, and don’t want to give any @warning as parameter.

But it shows that @warning para is not supplying after exec this proc

Msg 201, Level 16, State 4, Procedure SpSignup, Line 0
Procedure or function ‘SpSignup’ expects parameter ‘@warning’, which was not supplied.

and also it doesn’t shows the output ('email already exists')

Answer 1

you forgot to supply parameter @username into your procedure

declare @warning varchar(max)

exec SpSignup
    @username = 'Bill', 
    @email = '[e-mail]',
    @password = '12345',
    @warning = @warning output

select @warning

UPDATE: It’s not possible to return varchar variable from procedure, you can pass it as output parameter or you can just code select 'email already exists' or print 'email already exists'

alter proc SpSignup
(
    @username varchar(max),
    @email varchar(max),
    @password varchar(max)
)
as
begin
    if exists(select email from [login] where email=@email)
    begin
        select 'email already exists'
        print 'email already exists'
        return
    end

    insert into [login](username, email, password) values(@username, @email, @password)
end