MySQL常用查询总结

MySQL常用查询

在日常工作中，大部分项目采用的是MySQL作为数据库支撑，下面总结日常需要用到的一些比较实用的查询，后续会不断补充，感兴趣的小伙伴可以留言好用的查询语句，与君共勉。

查询示例

1. 查询数据库所有表明和对应的字段名称

select table_name, column_name from information_schema.columns where table_schema='db_name' and table_name in (select table_name from information_schema.tables where table_schema='db_name') ;

2. 关联查询数据只在左表存在数据的情况

select tcc.customer_id from TABLE_A tcc left join TABLE_B tcra on tcc.customer_id = tcra.customer_id and tcra.customer_id is null;

3. 关联查询数据不在内表存在数据的情况

select tmc.id from TABLE_A ta where id not in (select customer_id from TABLE_B tb where tb.status = 0 group by tb.customer_id) and ta.status = 1 order by ta.create_time desc ;

3.从一个表更新字段值到另一个表字段

update tableA as a join tableB as b on a.no=b.no set a.name=b.name where a.status=1

4.查询表字段及对应注释

SELECT TABLE_NAME 表名, COLUMN_NAME 列名, COLUMN_TYPE 数据类型, COLUMN_KEY 主键, IF(IS_NULLABLE='NO','是','否') AS '必填', COLUMN_COMMENT 注释 FROM information_schema.COLUMNS WHERE TABLE_SCHEMA='db_name' AND table_name in ('table_name_1','table_name_2','table_name_3');