Speed v8 PlanetScale MySQL db约束错误

Question

使用 Vitess v8（PlanetScale 数据库） Table:

CREATE TABLE `Channel` (
    `id` INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
    `guildId` INTEGER UNSIGNED NOT NULL,
    `name` VARCHAR(64) NOT NULL,
    `description` TEXT NULL,
    `createdAt` DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
    `position` INTEGER NOT NULL,
    `parentId` INTEGER NULL,
    `ratelimit` INTEGER NOT NULL DEFAULT 0,
    `type` ENUM('textChannel', 'categoryChannel') NOT NULL,

    INDEX `Channel_guildId_idx`(`guildId`),
    UNIQUE INDEX `Channel_guildId_name_key`(`guildId`, `name`),
    UNIQUE INDEX `Channel_guildId_position_key`(`guildId`, `position`),
    PRIMARY KEY (`id`)
) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

测试数据：

INSERT INTO Channel (id, guildId, name, position, type) VALUES (1, 1, 'ch1', 1, 'textChannel');
INSERT INTO Channel (id, guildId, name, position, type) VALUES (2, 1, 'ch2', 2, 'textChannel');
INSERT INTO Channel (id, guildId, name, position, type) VALUES (3, 1, 'ch3', 3, 'textChannel');

第一步：（如果你不明白为什么这一步很重要也没关系）

UPDATE `Channel` SET `position` = 0.5 WHERE `id` = 3;

Ergest 提供的已编辑查询：

UPDATE `Channel` AS `ch`
INNER JOIN ( 
  SELECT `id` as `id2`,
  ( SELECT COUNT(*)
    FROM (SELECT * FROM `Channel`) AS `b`
    WHERE `b`.`position` <= `a`.`position`
  ) AS `p`
  FROM `Channel` AS `a` WHERE `guildId` = 1
) AS `td` ON `ch`.`id` = `td`.`id2`
SET `ch`.`position` = `td`.`p`;

错误：

error: code = AlreadyExists desc = Duplicate entry '1-2' for key 'Channel.Channel_guildId_position_key' (errno 1062)

Answer 1

您正在使用 ORDER BY。

MySQL 文档：

Multiple-table syntax: For the multiple-table syntax, UPDATE updates rows in each table named in table_references that satisfy the conditions. Each matching row is updated once, even if it matches the conditions multiple times. For multiple-table syntax, ORDER BY and LIMIT cannot be used.

当你不使用 LIMIT

时，我认为在子查询中使用 ORDER BY position ASC 毫无意义

尝试使用 INNER JOIN:

UPDATE `Channel` AS `ch`,
INNER JOIN ( 
            SELECT`id`,
                      ( SELECT COUNT(*)
                        FROM `Channel` AS `b`
                        WHERE `b`.`position` <= `a`.`position`
                      ) AS `p`
           FROM `Channel` AS `a` WHERE `guildId` = 1
           ) AS `td` on   `ch`.`id` = `td`.`id`; 
SET `ch`.`position` = `td`.`p` ;

Speed v8 PlanetScale MySQL db约束错误

Vitess v8 PlanetScale MySQL db constraint error

mysql

innodb

sql-update

vitess

vitess.io