Return value in SQL Server stored procedure

Question

I have a stored procedure that has an if statement in it. If the number of rows counted is greater than 0 then it should set the only output parameter @UserId to 0<

Answer 1

@EmailAddress varchar(200),
@NickName varchar(100),
@Password varchar(150),
@Sex varchar(50),
@Age int,
@EmailUpdates int,
@UserId int OUTPUT
DECLARE @AA INT
SET @AA=(SELECT COUNT(UserId) FROM RegUsers WHERE EmailAddress = @EmailAddress)

IF @AA> 0
    BEGIN
        SET @UserId = 0
    END
ELSE
    BEGIN
        INSERT INTO RegUsers (EmailAddress,NickName,PassWord,Sex,Age,EmailUpdates) VALUES (@EmailAddress,@NickName,@Password,@Sex,@Age,@EmailUpdates)
        SELECT SCOPE_IDENTITY()
    END

END