SQL的学习
create database hpf; use hpf; create table hdfdf ( id int(10) NOT null auto_increment, uid varchar(10) not null default 0, remark text null, primary key (id) ) show tables; select * from hdfdf; select id as idenfiy from hdfdf; select * from test where id!=1; select * from test where id<>1; select * from test where id in (1,2); select * from test where id not in (1,2); select * from test where id between 1 and 3; select * from test where id not between 1 and 3; select * from test where id=1 and remark="学生"; select * from test group by remark; select * from test order by regdate (asc\desc); select * from test limit 0,3; select * from test ; select count(*) as num from test; select max(id) as num from test; select min(id) from test; select avg(id) from test; select sum(id) from test; select * from test where uid like '%王%'; alter table hdfdf drop remark; alter table hdfdf add remark text null after id; alter table hdfdf add name varchar(20) null; insert into test (uid,regdate,remark) values (5,now(),'老师'); update test set uid='万网' where id=5; delete from test where id=6 create table message( id tinyint(1) not null auto_increment, user varchar(25) not null, title varchar(50) not null, content tinytext not null, lastdate date not null, primary key (id) )engine=InnoDB default charset=gbk auto_increment=1; select * from message;
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