简单的列更改查询在 MySQL 5.7 中不起作用

Question

我有一个由 MySQL Workbench 8 创建的更新查询，它看起来如下：

-- MySQL Workbench Synchronization
-- Generated: 2019-12-16 00:30
-- Model: New Model
-- Version: 1.0
-- Project: Name of the project
-- Author: user0

SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='ALLOW_INVALID_DATES';

ALTER TABLE `best_bpgallery`.`k96qw_bpgallery_images` 
CHANGE COLUMN `language` `language` NCHAR(7) CHARACTER SET 'utf8mb4' COLLATE 'utf8mb4_unicode_ci' NOT NULL DEFAULT '*' ;


SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;

它对我来说看起来很好，但是当我运行它失败了：

Executing SQL script in server
ERROR: Error 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'CHARACTER SET 'utf8mb4' COLLATE 'utf8mb4_unicode_ci' NOT NULL DEFAULT '*'' at line 2
SQL Code:
        ALTER TABLE `best_bpgallery`.`k96qw_bpgallery_images` 
        CHANGE COLUMN `language` `language` NCHAR(7) CHARACTER SET 'utf8mb4' COLLATE 'utf8mb4_unicode_ci' NOT NULL DEFAULT '*' 

SQL script execution finished: statements: 3 succeeded, 1 failed

Fetching back view definitions in final form.
Nothing to fetch

我什至将查询与 ALTER TABLE documentation 进行了比较，它对我来说看起来不错。发生什么了？我错过了什么？

Answer 1

例如，您必须将 nchar 更改为 varchar。

ALTER TABLE `best_bpgallery`.`k96qw_bpgallery_images` 
CHANGE COLUMN `language` `language` VARCHAR(7) CHARACTER SET 'utf8mb4' COLLATE 'utf8mb4_unicode_ci' NOT NULL DEFAULT '*' ;

nchar 不支持字符集

简单的列更改查询在 MySQL 5.7 中不起作用

Simple column change query doesn' work in MySQL 5.7

mysql

mysql-workbench

mysql-5.7