mysql操作

1.查询select

SELECT column_name,column_name FROM table_name [WHERE Clause] [LIMIT N] [ OFFSET M]
WHERE 条件 name='Mary'
LIMIT 返回几条数据
OFFSET 从第几条开始

　

2.修改update 

UPDATE table_name SET field1=new-value1, field2=new-value2 [WHERE Clause]

　　

3.删除delete

DELETE FROM table_name [WHERE Clause]

　　

4.增加add

INSERT INTO table_name ( field1, field2,...fieldN ) VALUES ( value1, value2,...valueN );

　　

 

5.排序ORDER BY   ASC  DESC

 

6.包含有 like  WHERE run LIKE '%COM';   run字断中有.com

 

7联表查询 

（A）内连接：join，inner join

（B）外连接：left join，left outer join，right join，right outer join，union

（C）交叉连接：cross join

8.查询每天数据总量

select DATE_FORMAT(up_date,'%Y-%m-%d') as m,count(*) from log where up_date between '2018-02-02 09:18:36' and '2021-03-05 23:18:36' and type=1 group by m;