Question

我查看了大量的教程，手册和文档，但我仍然无法使用它。

我正在尝试使用phpMyAdmin创建存储过程。

我似乎无法在这里找到错误，sql错误是如此模糊......

CREATE PROCEDURE insertToonOneShot(IN locale CHAR(2), IN name VARCHAR(16), IN realm VARCHAR(24), IN faction CHAR(1), IN toon_level INT, IN class_name INT)
BEGIN
DECLARE @realmID INT;
DECLARE @classID INT;
DECLARE @toonID INT;
SET @realmID = SELECT id FROM realms WHERE realms.name = realm;
SET @classID = SELECT id FROM classes WHERE classes.name = class_name;
IF NOT @realmID IS NULL AND NOT @classID IS NULL AND @toonID IS NULL THEN
INSERT INTO 
toon (`locale`, `name`, `realm_id`, `faction`, `level`, `class_id`)
VALUES
(locale, name, @realmID, faction, toon_level, @classID);
END IF;
END;

我现在得到的错误是：

＃1064 - 您的SQL语法出错;检查手册对应于您的MySQL服务器版本，以便使用正确的语法靠近@realmID INT; DECLARE @classID INT; DECLARE @toonID INT; SET @rea 在第3行

可能是我曾经做过的更令人沮丧的事情之一...

我在网上看到很多教程在变量声明中使用@符号，而其他人没有使用它，我甚至看到一些使用VAR而不是DECLARE。什么是正确的语法？...

Answer 1

当你有子查询时，它需要有括号。这些行：

SET @realmID = SELECT id FROM realms WHERE realms.name = realm;
SET @classID = SELECT id FROM classes WHERE classes.name = class_name;

应该是：

SET @realmID = (SELECT id FROM realms WHERE realms.name = realm);
SET @classID = (SELECT id FROM classes WHERE classes.name = class_name);

或者，更好的是，您不需要set：

SELECT @realmID := id FROM realms WHERE realms.name = realm;
SELECT @classID := id FROM classes WHERE classes.name = class_name;

Answer 2

这就是诀窍：

CREATE PROCEDURE insertToonOneShot(IN locale CHAR(2), IN name VARCHAR(16), IN realm VARCHAR(24), IN faction CHAR(1), IN toon_level INT, IN class_name VARCHAR(12))
BEGIN
SELECT @realmID := id FROM realms WHERE realms.name = realm;
SELECT @classID := id FROM classes WHERE classes.name = class_name;
SELECT @toonID := id FROM toon WHERE toon.name = name AND toon.realm_id = @realmID;
IF NOT @realmID IS NULL AND NOT @classID IS NULL AND @toonID IS NULL
THEN 
INSERT INTO toon (`locale`, `name`, `class_id`, `realm_id`, `faction`, `level`)
VALUES (locale, name, @classID, @realmID, faction, toon_level);
END IF;
END;
//

显然声明声明不是必需的......谁会知道？

感谢Gordon Linoff指出我正确的方向。

Answer 3

老问题，但我认为值得一提的是，似乎是会话变量（以@为前缀）与程序变量混淆，而不是。

接受的解决方案可以解决错误，但如果在过程外定义变量然后在内部使用，则可能会引入与变量范围相关的问题。解决此问题的正确方法是仅使用过程变量：

DELIMITER $$

CREATE PROCEDURE insertToonOneShot(
    IN locale CHAR(2),
    IN name VARCHAR(16),
    IN realm VARCHAR(24),
    IN faction CHAR(1),
    IN toon_level INT,
    IN class_name INT
)
BEGIN
    DECLARE realmID INT;
    DECLARE classID INT;

    SELECT id INTO realmID FROM realms WHERE realms.name = realm LIMIT 1;
    SELECT id INTO classID FROM classes WHERE classes.name = class_name LIMIT 1;
    IF realmID IS NOT NULL AND classID IS NOT NULL THEN
        INSERT INTO toon (`locale`, `name`, `realm_id`, `faction`, `level`, `class_id`)
        VALUES (locale, name, realmID, faction, toon_level, classID);
    END IF;
END$$

DELIMITER ;

MYSQL存储过程：变量声明和条件语句

3 个答案: