mysql数据库aaa下的所有表和所有字段使用utf8mb4_general_ci 字符集,直接给出答案
时间: 2023-03-01 21:40:52 浏览: 68
Here's the SQL code to change the character set and collation for all tables in a database named "aaa" in MySQL:
```
ALTER DATABASE aaa CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci;
```
This will change the character set and collation of the database as a whole. To change the character set and collation for all tables and columns in the database, you can use the following code:
```
SET FOREIGN_KEY_CHECKS=0;
SELECT concat('ALTER TABLE ', table_name, ' CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;')
FROM information_schema.tables
WHERE table_schema = 'aaa' AND table_collation != 'utf8mb4_general_ci';
SET FOREIGN_KEY_CHECKS=1;
```
This code will select all tables in the "aaa" database that have a collation different from `utf8mb4_General_ci` and generate an `ALTER TABLE` statement for each of them. The `SET FOREIGN_KEY_CHECKS=0` statement disables foreign key checks, allowing the collation change to occur, while `SET FOREIGN_KEY_CHECKS=1` re-enables foreign key checks.
Note: Before running the above code, make sure to backup your data.