MySql - if exists clause in stored procedure - mysql

Question

I'm working on login/register module of my program based on a tutorial I found.
Everything worked fine but then I switched from MSSql to MySql database.
The problem is I can't rewrite my InsertUser procedure. This procedure takes 3 parameters (username, password and email) and can return 3 different values
-1 if username is already used
-2 if email is already used
id of new row if registration is successful
I tried to write it like this:
DELIMITER $$
CREATE PROCEDURE InsertUser(
IN username VARCHAR(50),
IN pass VARCHAR(255),
IN email VARCHAR(50))
BEGIN
IF (SELECT Id FROM Users WHERE UserName=username) THEN
BEGIN
SELECT -1;
END;
ELSEIF (SELECT Id FROM Users WHERE Email=email)
THEN
BEGIN
SELECT -2;
END;
ELSE
BEGIN
INSERT INTO Users (UserName, Password, RegDate, Email) VALUES(username, pass, CURDATE(), email);
SELECT LAST_INSERT_ID();
END;
END IF;
END $$
DELIMITER ;
When I try to create this procedure using the above code from Visual Studio I get error (wrong syntax). However there is no error if I do it from phpmyadmin page. But it doesn't work at all (returns nothing) regardless of arguments I provide. I'm using phpmyadmin page and execute procedure option to test it.
Here is original T-Sql code:
CREATE PROCEDURE [dbo].[Insert_User]
#Username NVARCHAR(20),
#Password NVARCHAR(20),
#Email NVARCHAR(50)
AS
BEGIN
SET NOCOUNT ON;
IF EXISTS(SELECT Id FROM Users WHERE Username = #Username)
BEGIN
SELECT -1 -- Username exists.
END
ELSE IF EXISTS(SELECT Id FROM Users WHERE Email = #Email)
BEGIN
SELECT -2 -- Email exists.
END
ELSE
BEGIN
INSERT INTO [Users]
([Username]
,[Password]
,[Email]
,[RegDate])
VALUES
(#Username
,#Password
,#Email
,GETDATE())
SELECT SCOPE_IDENTITY() -- UserId
END
END
Any ideas?

Answer 1

6.10.1 Using Stored Routines from Connector/Net
...
Unlike the command-line and GUI clients, you are not required to specify a special delimiter when creating stored procedures in Connector/Net.
...
One option in MySQL (command-line):
DELIMITER $$
CREATE PROCEDURE `InsertUser` (
IN `_username` VARCHAR(50),
IN `_pass` VARCHAR(255),
IN `_email` VARCHAR(50)
)
BEGIN
IF (SELECT `Id` FROM `Users` WHERE `UserName` = `_username`) THEN
SELECT -1;
ELSEIF (SELECT `Id` FROM `Users` WHERE `Email` = `_email`) THEN
SELECT -2;
ELSE
INSERT INTO `Users` (`UserName`, `Password`, `RegDate`, `Email`)
VALUES (`_username`, `_pass`, CURDATE(), `_email`);
SELECT LAST_INSERT_ID();
END IF;
END$$
DELIMITER ;

Answer 2

Thank you, but I solved it myself. I don't know why I wanted so badly to use EXISTS function:) I got rid of it and now it works:
BEGIN
IF(SELECT Id FROM Users WHERE UserName=username) IS NOT NULL THEN
SELECT -1;
ELSEIF (SELECT Id FROM Users WHERE Email=email) IS NOT NULL THEN
SELECT -2;
ELSE
INSERT INTO Users(UserName, Password, RegDate, Email) VALUES (username, pass, CURDATE(), email);
SELECT LAST_INSERT_ID();
END IF;
END