1 insert

insert into table_name(column_list) values(value_list);
可以完全不指定列名，值的顺序同创建表时一致，不推荐；建议指定列名，列名顺序自定义，值顺序同列顺序
insert into table_name(column_list) select value_list from table_name2;

drop table if exists tb_emp1;
create table tb_emp1(
id int primary key,
name varchar(10)
);


insert into tb_emp1(id,name) values('1','a');
insert into tb_emp1(id,name) values('2','b');
insert into tb_emp1(id,name) values('3','c');
insert into tb_emp1(id,name) values('4','d');
insert into tb_emp1(id,name)  select id+4,name from tb_emp1;
select * from tb_emp1;

1 a
2 b
3 c
4 d
5 a
6 b
7 c
8 d

2 update

update table_name set column_name1=value1[,column_name2=value2...] [where condition]

update tb_emp1 set id=9,name='e' where id=1 and name='a'; 
select * from tb_emp1;

2 b
3 c
4 d
5 a
6 b
7 c
8 d
9 e

3 delete

delete from table_name [where condition]

delete from tb_emp1 s where id=9; 
select * from tb_emp1;

2 b
3 c
4 d
5 a
6 b
7 c
8 d