mysql - 操作 '=' 的排序规则 (utf8_unicode_ci,IMPLICIT) 和 (utf8_general_ci,IMPLICIT) 的非法混合

Question

MySql 上的错误信息:

Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '='

我浏览了其他几篇帖子，但无法解决这个问题。受影响的部分与此类似:

CREATE TABLE users (
    userID INT UNSIGNED NOT NULL AUTO_INCREMENT,
    firstName VARCHAR(24) NOT NULL,
    lastName VARCHAR(24) NOT NULL,
    username VARCHAR(24) NOT NULL,
    password VARCHAR(40) NOT NULL,
    PRIMARY KEY (userid)
) ENGINE = INNODB CHARACTER SET utf8 COLLATE utf8_unicode_ci;

CREATE TABLE products (
    productID INT UNSIGNED NOT NULL AUTO_INCREMENT,
    title VARCHAR(104) NOT NULL,
    picturePath VARCHAR(104) NULL,
    pictureThumb VARCHAR(104) NULL,
    creationDate DATE NOT NULL,
    closeDate DATE NULL,
    deleteDate DATE NULL,
    varPath VARCHAR(104) NULL,
    isPublic TINYINT(1) UNSIGNED NOT NULL DEFAULT '1',
    PRIMARY KEY (productID)
) ENGINE = INNODB CHARACTER SET utf8 COLLATE utf8_unicode_ci;

CREATE TABLE productUsers (
    productID INT UNSIGNED NOT NULL,
    userID INT UNSIGNED NOT NULL,
    permission VARCHAR(16) NOT NULL,
    PRIMARY KEY (productID,userID),
    FOREIGN KEY (productID) REFERENCES products (productID) ON DELETE RESTRICT ON UPDATE NO ACTION,
    FOREIGN KEY (userID) REFERENCES users (userID) ON DELETE RESTRICT ON UPDATE NO ACTION
) ENGINE = INNODB CHARACTER SET utf8 COLLATE utf8_unicode_ci;

我使用的存储过程是这样的:

CREATE PROCEDURE updateProductUsers (IN rUsername VARCHAR(24),IN rProductID INT UNSIGNED,IN rPerm VARCHAR(16))
BEGIN
    UPDATE productUsers
        INNER JOIN users
        ON productUsers.userID = users.userID
        SET productUsers.permission = rPerm
        WHERE users.username = rUsername
        AND productUsers.productID = rProductID;
END

我正在使用 php 进行测试，但使用 SQLyog 时也会出现同样的错误。我还测试过重新创建整个数据库，但效果不佳。

任何帮助将不胜感激。

Answer 1

存储过程参数的默认排序规则是utf8_general_ci，你不能混合排序规则，所以你有四种选择:

选项 1:将 COLLATE 添加到您的输入变量:

SET @rUsername = ‘aname’ COLLATE utf8_unicode_ci; -- COLLATE added
CALL updateProductUsers(@rUsername, @rProductID, @rPerm);

选项 2:将 COLLATE 添加到 WHERE 子句:

CREATE PROCEDURE updateProductUsers(
    IN rUsername VARCHAR(24),
    IN rProductID INT UNSIGNED,
    IN rPerm VARCHAR(16))
BEGIN
    UPDATE productUsers
        INNER JOIN users
        ON productUsers.userID = users.userID
        SET productUsers.permission = rPerm
        WHERE users.username = rUsername COLLATE utf8_unicode_ci -- COLLATE added
        AND productUsers.productID = rProductID;
END

选项 3:将其添加到 IN 参数定义中(MySQL 5.7 之前):

CREATE PROCEDURE updateProductUsers(
    IN rUsername VARCHAR(24) COLLATE utf8_unicode_ci, -- COLLATE added
    IN rProductID INT UNSIGNED,
    IN rPerm VARCHAR(16))
BEGIN
    UPDATE productUsers
        INNER JOIN users
        ON productUsers.userID = users.userID
        SET productUsers.permission = rPerm
        WHERE users.username = rUsername
        AND productUsers.productID = rProductID;
END

选项 4:更改字段本身:

ALTER TABLE users CHARACTER SET utf8 COLLATE utf8_general_ci;

除非您需要按 Unicode 顺序对数据进行排序，否则我建议您更改所有表以使用 utf8_general_ci 排序规则，因为它不需要更改代码，并且会稍微加快排序速度。

更新:utf8mb4/utf8mb4_unicode_ci 现在是首选的字符集/整理方法。建议不要使用 utf8_general_ci，因为性能提升可以忽略不计。见 https://stackoverflow.com/a/766996/1432614