[英]MySQL Stored Procedure - IF EXISTS … THEN returning unexpected result
The below is my Stored Procedure(Routine) to check whether or not a user with Username(input) exists in the database. 以下是我的存储过程(例程),用于检查数据库中是否存在具有Username(输入)的用户 。 Inside the database, I already have a user with Username - 'dev'.
在数据库内部,我已经有一个用户名-'dev'的用户。 However, when I ran the below routine, it returned me with res = 1 , which I expected it to be -1 .
但是,当我运行以下例程时,它返回res = 1 ,我希望它是-1 。
I called the routine this way. 我以这种方式调用了例程。 Please correct me too if I am calling it the wrong way.
如果我打错了电话,也请纠正我。 I am really new to MySQL Routines.
我真的是MySQL例程的新手。
CALL usp_GetUserValidation ('dev', @ErrorCode)
致电usp_GetUserValidation('dev',@ErrorCode)
Can any MySQL Routine pros here enlighten me on this? 这里的任何MySQL Routine专家都能启发我吗? Thank you in advance guys :)
预先谢谢你们:)
DELIMITER $$
CREATE PROCEDURE usp_GetUserValidation(IN `@Username` VARCHAR(255), OUT `@ErrorCode` INT)
LANGUAGE SQL
NOT DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT 'To validate user login'
BEGIN
IF EXISTS
(SELECT UserID
FROM mt_User
WHERE UserName = @Username)
THEN
SET @ErrorCode = -1;
ELSE
SET @ErrorCode = 1;
END IF;
SELECT @ErrorCode AS res;
END$$
DELIMITER ;
It was simply your naming conventions for the parameters. 只是您对参数的命名约定。 It is finicky and does not like User Variable
@
signs in them. 这很挑剔,并且不喜欢在其中输入用户变量
@
。
You are just testing I can see, as you are returning both a resultset with the info and the OUT
variable. 我所看到的只是测试,因为您同时返回了带有info和
OUT
变量的结果集。
drop procedure if exists usp_GetUserValidation;
DELIMITER $$
CREATE PROCEDURE usp_GetUserValidation(IN pUsername VARCHAR(255), OUT pErrorCode INT)
LANGUAGE SQL
NOT DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT 'To validate user login'
BEGIN
IF EXISTS
(SELECT UserID
FROM mt_User
WHERE UserName = pUsername)
THEN
SET pErrorCode = -1;
ELSE
SET pErrorCode = 1;
END IF;
SELECT pErrorCode AS res;
END$$
DELIMITER ;
Schema: 架构:
-- drop table if exists mt_user;
create table mt_User
( UserID int auto_increment primary key,
UserName varchar(100) not null,
unique key(UserName)
);
insert mt_User(UserName) values ('dev');
select * from mt_User;
Test: 测试:
set @var1:=-4;
call usp_GetUserValidation('dev',@var1);
-- returns (-1) ---- Yea, we like that
select @var1;
-- (-1)
set @var1:=-4;
call usp_GetUserValidation('dev222',@var1);
-- returns 1 ---- Yea, we like that
select @var1;
-- 1
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