数据库增删改查等操作

//插入数据

INSERT INTO `user` (`name`, `sex`, `age`, `email`, `password`, `status`, `create_time`) VALUES ('金庸', '0', '90', 'email@php.cn', sha1(123456), '1', '1548656957');

//简化插入数据

INSERT `user` VALUES (null,'林清玄', '1', '90', 'email@php.cn', sha1(123456), '1', now()),(null,'唐伯虎', '1', '90', 'email@php.cn', sha1(123456), '1', now())

//更新语句

UPDATE `user` SET `age` = 78,`email` = 'php@php.cn' WHERE `id` = 20

//查询

SELECT * FROM `user`;

SELECT `name`,`age` FROM `user`;

SELECT `name`,`age` FROM `user` WHERE status = 1 ORDER BY `age` LIMIT 2;

//SELECT计算

SELECT 20*30 AS result;

//字符串拼接

SELECT concat('*',`id`,`name`) AS `user_info` FROM `user` WHERE `status` =1;

SELECT concat_ws('*',`id`,`name`) AS `user_info` FROM `user` WHERE `status` =1;

SELECT COUNT(*) AS res FROM `user` WHERE status =1

//删除

DELETE FROM `user` WHERE `id`=16

//主键排序

truncate table `user`

//主键排序

ALTER TABLE `user` DROP `id`;

ALTER TABLE `user` ADD `id` int(6) PRIMARY KEY NOT NULL AUTO_INCREMENT FIRST;