创建表
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
`date1` datetime(6) DEFAULT NULL,
`date2` date DEFAULT NULL,
`date3` timestamp(6) NULL DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
SET FOREIGN_KEY_CHECKS = 1;
查询
SELECT [ DISTINCT ] select_list
[ INTO new_table ]
FROM table_name
[ WHERE search_condition ]
[ GROUP BY group_by_expression ]
[ HAVING search_condition ]
[ ORDER BY order_by_expression [ ASC | DESC ] ]
视图:CRUD同表
select `user`.`id` AS `id_v`,`user`.`name` AS `name_v`,`user`.`age` AS `age_v` from `user`
别名
select name "名字" from user;
select name ’名字‘ from user;
select name 名字 from user;
select name as "名字" from user;
select name as ’名字‘ from user;
select name as 名字 from user;
嵌入行内的注释语句:
“--”(双减号)用来创建单行文本注释语句。
块注释语句:
在注释文本的起始处输入“/*”,在注释文本的结束处输入“*/”,就可以使两个符号间的所有字符称为注释语句,从而可以创建包含多行的块注释语句。
限制条数
LIMIT m OFFSET n
条件
=
>
<
>=
<=
!>
!<
!= / <>
逻辑运算符:注意他们的优先级
NOT
AND
OR
通配符 : % _ []
转义符
查询指定行
查询随机一行
(未完待续)