[大数据]Mysql：修改字符集和排序规则

说明：
排序规则生效优先级：字段 》表 》库

一、数据库

— 修改数据库字符集和排序规则

alter database xc  character 
set utf8 collate utf8_general_ci;

— 查看数据库的字符集

select * from information_schema.schemata 
where schema_name = 'db_name';

二、数据表

— 修改表默认的字符集

alter table table_name character 
set gbk collate gbk_bin;

— 查看表的字符集

select * from information_schema.tables 
where table_schema = 'db_name' 
and table_name = 'table_name';

三、表字段

— 修改字段的字符集

ALTER TABLE table_name 
CHANGE `column_name` `column_name` VARCHAR(40) 
CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

— 批量修改表字段的字符集

alter table table_name convert to character 
set gbk collate gbk_bin;

— 查看字段的字符集

select * from information_schema.columns 
where table_schema = 'db_name' 
and table_name = 'table_name';