数据定义语言DDL
create database db_name;
create table table_name (column_name data_type,...);
create view view_name as select .....;
create index on table_name (column_name,...);
drop database db_name;
drop table table_name;
drop view view_name;
drop index table_name.index_name;（不同sql方言不同，这是sql server的写法）
alter table table_name
add column_name data_type
drop column_name;
change column_name new_column_name data_type,...
modify column_name data_type,...
数据操纵语言DML
select column_name from table_name where ...
update table_name set column_name=value where ...
insert into table_name (cloumn_name,...) values (value1,...)
delete from table_name where ...
数据控制语言DCL：控制权限
grant select,updat,insert,delete on table_name to 'user_name'@'host_name';
revoke select,updat,insert,delete on table_name to 'user_name'@'host_name';
事务控制语言TCL：控制事务
commit
rollback
