mysql数据具体操作
作者:互联网
1.建表操作
前面提到的是简单的建表,这里需要提到一下外键。
create table userinfo2( id int auto_increment primary key, name char(10), gender char(10), email varchar(64) )engine=innodb default charset=utf8; create table host( id int auto_increment primary key, hostname char(64) )engine=innodb default charset=utf8; create table user2host( id int auto_increment primary key, userid int not null, hostid int not null, unique uq_user_host (userid,hostid), CONSTRAINT fk_u2h_user FOREIGN key (userid) REFERENCES userinfo2(id), CONSTRAINT fk_u2h_host FOREIGN key (hostid) REFERENCES host(id) )engine=innodb default charset=utf8;View Code
补充:建表时还可以设置自增列从几开始
CREATE TABLE s2( tid INT auto_increment PRIMARY KEY, tname VARCHAR(32) )ENGINE=INNODB auto_increment=4 DEFAULT charset=utf8;View Code
如果建表时没有设置,后续可以修改
ALTER TABLE s2 AUTO_INCREMENT = 100;View Code
2.增
1). 插入完整数据(顺序插入)
语法一:
INSERT INTO 表名(字段1,字段2,字段3…字段n) VALUES(值1,值2,值3…值n);
语法二:
INSERT INTO 表名 VALUES (值1,值2,值3…值n);
2). 指定字段插入数据
语法:
INSERT INTO 表名(字段1,字段2,字段3…) VALUES (值1,值2,值3…);
3). 插入多条记录
语法:
INSERT INTO 表名 VALUES
(值1,值2,值3…值n),
(值1,值2,值3…值n),
(值1,值2,值3…值n);
4). 插入查询结果
语法:
INSERT INTO 表名(字段1,字段2,字段3…字段n)
SELECT (字段1,字段2,字段3…字段n) FROM 表2
WHERE …;
INSERT INTO s2(name) SELECT tname FROM teacher;View Code
3.删
delete from tb12; delete from tb12 where id !=2 delete from tb12 where id =2 delete from tb12 where id > 2 delete from tb12 where id >=2 delete from tb12 where id >=2 or name='alex'View Code
4.改
语法: UPDATE 表名 SET 字段1=值1, 字段2=值2, WHERE CONDITION; 示例: UPDATE mysql.user SET password=password(‘123’) where user=’root’;View Code
5.查
查是重点另开一贴再写
标签:Code,数据,tb12,表名,字段,具体操作,mysql,where,id 来源: https://www.cnblogs.com/xufengnian/p/10579267.html