下面的SQL語句該怎麼寫啊？

IF  EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[TheWay_Membership_CreateUser]') AND OBJECTPROPERTY(id,N'IsProcedure') = 1)
DROP PROCEDURE [dbo].[TheWay_Membership_CreateUser]
GO

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER OFF
GO

CREATE PROCEDURE [dbo].[TheWay_Membership_CreateUser]
    @UserName                               nvarchar(256),
    @Password                               nvarchar(128),
    @Salt                           nvarchar(128),
    @Email                                  nvarchar(256),
    @PasswordQuestion                       nvarchar(256),
    @PasswordAnswer                         nvarchar(128),
    @IsApproved                             bit,
    @UniqueEmail                            int      = 0,
    @PasswordFormat                         int      = 0,
    @NewUserID  int OUTPUT 
AS
    PRINT 'ERROR: No title_id was specified.'
    SELECT @NewUserID=0    
   --檢查是否已經有相同的使用者名稱存在，存在則返回-1
   IF ( EXISTS ( SELECT UserID FROM   dbo.TheWay_Users WHERE  UserName = @UserName ) )
         BEGIN
            RETURN(-1)
         END
   ELSE
        IF(@UniqueEmail = 1)
            BEGIN--檢查是否要求要不重複的Email，如果要求，則檢查是否已經存在相同的Email，如果存在返回-2
                IF(EXISTS(SELECT UserID FROM dbo.TheWay_Users WHERE Email = @Email))
                    BEGIN
                        RETURN(-2)
                    END
            END
  ELSE
    BEGIN
        --插入必要的資料到資料庫，並將UserID查詢返回，成功則返回1
        INSERT INTO dbo.TheWay_Users
        (
        UserName,
        Password,
        PasswordFormat,
        Salt,
        PasswordQuestion,
        PasswordAnswer,
        Email,
        IsApproved
        )
        VALUES
        (
        @UserName,
        @Password,
        @PasswordFormat,
        @Salt,
        @PasswordQuestion,
        @PasswordAnswer,
        @Email,
        @IsApproved        
        )
        IF(EXISTS(SELECT @NewUserID=UserID FROM dbo.TheWay_Users Where UserName=@UserName))
            BEGIN
                RETURN(1)
            END
        ELSE
            BEGIN
                RETURN(-3)
            END
        END
GO

我是個菜鳥，幫幫忙。