-- 創建數據庫
CREATE DATABASE dbname DEFAULT CHARSET utf8 COLLATE utf8_general_ci;
-- 創建表
CREATE TABLE `tb` (
  `id` int(5) NOT NULL AUTO_INCREMENT,
  `name` char(15) NOT NULL,
  `alias` varchar(10) DEFAULT NULL,
  `email` varchar(30) DEFAULT NULL,
  `password` varchar(20) NOT NULL,
  `phone` char(11) DEFAULT ‘13800138000‘,
  PRIMARY KEY (`id`,`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 進入dbname數據庫
mysql> use dbname
Database changed
# 查看當前庫所有的表
mysql> show tables;
+------------------+
| Tables_in_dbname |
+------------------+
| tb               |
+------------------+
1 row in set (0.00 sec)
# 查看tb表內的內容
mysql> select * from tb;
Empty set (0.00 sec)

-- 插入單條數據
insert into tb(name,email,password) values("ansheng","[email protected]

mysql> select * from tb;
+----+---------+-------+-------------------------+----------+-------------+
| id | name    | alias | email                   | password | phone       |
+----+---------+-------+-------------------------+----------+-------------+
|  2 | ansheng | NULL  | [email protected]

把別的表的數據插入當前表

查看tb_copy表內的內容

mysql> select * from tb_copy;
+----+--------+-------+-------+----------+-------------+
| id | name   | alias | email | password | phone       |
+----+--------+-------+-------+----------+-------------+
|  5 | hello  | NULL  | NULL  | 1        | 13800138000 |
|  6 | word   | NULL  | NULL  | 2        | 13800138000 |
|  7 | python | NULL  | NULL  | 3        | 13800138000 |
+----+--------+-------+-------+----------+-------------+
3 rows in set (0.00 sec)

把tb_copy表內的name,email,password列插入到tb表中

insert into tb (name, email, password) select name,email,password from tb_copy;

查詢tb內的內容

mysql> select * from tb;
+----+---------+-------+-------------------------+----------+-------------+
| id | name    | alias | email                   | password | phone       |
+----+---------+-------+-------------------------+----------+-------------+
|  2 | ansheng | NULL  | [email protected] | as       | 13800138000 |
|  3 | as      | NULL  | [email protected]         | pwd      | 13800138000 |
|  4 | info    | NULL  | [email protected]      | i        | 13800138000 |
|  5 | hello   | NULL  | NULL                    | 1        | 13800138000 |
|  6 | word    | NULL  | NULL                    | 2        | 13800138000 |
|  7 | python  | NULL  | NULL                    | 3        | 13800138000 |
+----+---------+-------+-------------------------+----------+-------------+
6 rows in set (0.00 sec)

刪除表內數據

-- 刪除表內的所有內容
delete from tb_copy;

-- 刪除表內某一條數據
delete from tb where id=2 and name="ansheng";

更改表內數據

update tb set name="as" where id="3";

查

-- 查詢表內所有內容
select * from tb;
-- 帶條件的查詢表內的內容
select * from tb where id > 4;

查詢的時候指定最後一列的名稱

mysql> select id,name as username from tb where id > 4;
+----+----------+
| id | username |
+----+----------+
|  5 | hello    |
|  6 | word     |
|  7 | python   |
+----+----------+
3 rows in set (0.00 sec)

其他操作

條件

-- 多條件查詢
select * from tb where id>3 and name="hello" and password="1";
-- 查詢指定範圍
select * from tb where id between 4 and 6;
-- 查詢括號內存在的數據
select * from tb where id in (4,6);
-- 查詢括號內不存在的數據
select * from tb where id not in (4,6);
-- 以別的表的內容為查詢條件
select * from tb where id in (select id from tb_copy);

通配符

-- 以p開頭的所有（多個字符串）
select * from tb where name like "p%";
-- 以p開頭的所有（一個字符）
select * from tb where name like "p%";

限制

-- 前三行數據
select * from tb limit 3;
-- 從第2行開始的3行
select * from tb limit 2,3;
-- 從第4行開始的5行
select * from tb limit 5 offset 4;

排序

-- 根據"name"列從小到大排列
select * from tb order by name asc;
-- 根據"name"列從大到小排列
select * from tb order by name desc;
-- 根據 “列1” 從大到小排列，如果相同則按列2從小到大排序
select * from 表 order by 列1 desc,列2 asc;

分組

select id from tb group by id;
select id,name from tb group by id,name;
select num,nid from 表  where nid > 10 group by num,nid order nid desc;
select num,nid,count(*),sum(score),max(score),min(score) from 表 group by num,nid;
select num from 表 group by num having max(id) > 10;

特別的：group by 必須在where之後，order by之前

連表

無對應關系則不顯示

select A.num, A.name, B.name from A,B where A.nid = B.nid;

無對應關系則不顯示

select A.num, A.name, B.name from A inner join B on A.nid = B.nid;

A表所有顯示，如果B中無對應關系，則值為null

select A.num, A.name, B.name from A left join B on A.nid = B.nid;

B表所有顯示，如果B中無對應關系，則值為null

select A.num, A.name, B.name from A right join B on A.nid = B.nid;

組合

組合，自動處理重合

select nickname from A union select name from B;

組合，不處理重合

select nickname from A union all select name from B;

#Python全棧之路

3Python全棧之路系列之MySQL表內操作