MySQL操作記錄

創建一張數據表

create table users(
id smallint unsigned primary key auto_increment,
username varchar(20) not null,
password varchar(32) not null,
age tinyint unsigned not null default 10,
sex Boolean
);

插入單值

insert users values(NULL,'tom','123',25,1);
insert users values(DEFAULT,'john','456',25,1);
用數學表達式也可以插入

插入多個值

insert users values(DEFAULT,'john','456',25,1),(NULL,'tom','123',25,1);

INSERT-SET方法可以使用子查詢

INSERT users set username = 'Ben',password = '456';

UPDATE語句 更新記錄
單表更新

update users set age = age + 5;//更新所有的列
update users set age = age - id,sex=0;//特定的修改
update users set age = age + 10 where id % 2 =0;//利用where語句

單表刪除

delete from users where id = 6;

limit語句

select * from users limit 2;//返回兩條
select * from users limit 2,2;//返回id爲3，4的兩條，前面爲索引，後面爲個數

insert test(username) select username from user where age >= 30;//寫入指定的數據表

Select語句

select username,id from users;
select username as tang ,id from users;//使用別名

group by關鍵詞

select sex from users group by sex;

having 語句

select sex,age from users group by sex having age >35;

order by

order by id desc;//降序，由大到小
order by id,age desc;//降序，id優先