<?php
/**
* 常用的增删改查语句(CURD)：Create,Update,Read,Delete
* 添加：INSERT INTO 表名(字段列表) VALUES(值列表);
* 查询：SELECT 字段列表 FROM 表名 WHERE 查询条件 ORDER BY 排序条件 LIMIT 数量;
* 更新：UPDATE 表名 SET 字段=值,......WHIER 更新条件;
* 删除：DELETE FROM 表名 WHERE 删除条件;
*/
//添加操作
INSERT INTO `user`(`name`,`sex`,`age`,`email`,`password`,`status`,`create_time`) VALUES('杨过','0','34','yg@php.cn','sha1(123456)','1','1555484389');
//简写
INSERT `user` VALUES(null,'洪七公',0,67,'hq@php.cn',sha1(123456),1,1555484389);
//同时添加多条值
INSERT user VALUES(null,'杨康',0,26,'yk@php.cn',sha1(123456),1,1555484389),
(null,'欧阳克',0,25,'oyk@php.cn',sha1(123456),1,1555484389);
//更新操作
UPDATE `user` SET `age`=36 WHERE `id`=1;
//更新多条字段
UPDATE `user` SET `age`=56,`status`=0 WHERE `id`=1;
//查询操作
SELECT *FROM `user`;
SELECT `name`,`sex`,`age`,`email` FROM `user`;
SELECT `name`,`sex`,`age`,`email`,`status` FROM `user` WHERE `status`=1;
SELECT `name`,`sex`,`age`,`email`,`status` FROM `user` WHERE `status`=1 ORDER BY `age`;
SELECT `name`,`sex`,`age`,`email`,`status` FROM `user` WHERE `status`=1 ORDER BY `age` LIMIT 2;
//执行运算
SELECT 15*30 AS RESULT;
//字符串的拼接
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;
//查询表中的记录数
SELECT COUNT(*) AS STATISTICS FROM `user`;
SELECT COUNT(*) AS STATISTICS FROM `user`WHERE `status`=1 ;
//删除操作
DELETE FROM `user` WHERE `id`=3;
truncate table `user`;//清空表
//id重排
ALTER TABLE `user` DROP `id`;
ALTER TABLE `user` ADD `id` int(5) PRIMARY KEY NOT NULL AUTO_INCREMENT FIRST;
