mysql 注释:
- 多行注释用/*和*/
- 单行注释用-- 代替
select * from lilitest;
结果:
DML语句如下:
select * from lilitest where name like '%guo%'; -- 模糊查询
insert into lilitest(id,name,age)values(4,"zus",34),(5,"zhaoli",35),(6,"lik",67); -- 插入
delete from lilitest where name="lik";-- DELETE语句
update lilitest set age=57 where name ="zhaoli";-- update talbe1更新语句
select * from lilitest ORDER BY id,age ;-- 排序--
select count(id) from lilitest ;-- 求总条数
select sum(age) from lilitest;-- 求age总和
select avg(age) from lilitest; -- 求age 平均数
SELECT max(age) from lilitest; -- 求age最大值
select min(age) from lilitest; -- 求age最小值