create table t1(id int primary key,name varchar(10));
create table t2(id int primary key auto_increment,name varchar(10));
字段注释 comment
show variables like '%autocommit%';
set autocommit=0;
commit;
rollback;
savepoint s1;
rollback to s1;
truncate table 表名;
create table t_int(num int(10) zerofill);
int(m)
bigint(m)
double(m,d)
decimal(m,d)
char(10)
varchar(10)
text(10)
date
time
datetime
timestamp
is null
is not null
别名
select ename 名字 from emp;
去重
select distinct job from emp;