DML语句
查询语句---select
select * from XX表 where 范围
插入语句---insert into xxx values
insert into xx表(xx字段,xx字段...) values(值1,值2...)
插入语多条数据
INSERT INTO table_name (field1, field2,...fieldN) VALUES (valueA1,valueA2,...valueAN),(valueB1,valueB2,...valueBN),(valueC1,valueC2,...valueCN)......;
删除语句---delete
delete from XX表 where 范围
更新语句---update set
update XX表 set XX字段=XX值 where 范围
模糊查找---关键字:like
select *from xx表 where 字段名 like '%值%'
排序---order by desc
select *from XX表 order by xx字段..desc
总数---count(*)
select count(*) as totalcount from xx表
求和---sum(xx字段)
select sum(xx字段)from xx表
平均数---avg(xx字段)
select avg(xx字段)from xx表
最大---max(xx字段)
select max(xx字段)from xx表
最小--min(xx字段)
select min(xx字段)from xx表