MySQL復制表-INSERT INTO SELECT

轉自：https://www.cnblogs.com/yy20141204bb/p/8409988.html

基礎table為：

mysql> select * from staff;
+----+----------+-------+
| id | name     | slary |
+----+----------+-------+
|  3 | haofugui | 10000 |
|  4 | guoming  |  3500 |
|  5 | haotian  |  2900 |
+----+----------+-------+
3 rows in set (0.00 sec)

mysql> describe staff;
+-------+----------+------+-----+---------+----------------+
| Field | Type     | Null | Key | Default | Extra          |
+-------+----------+------+-----+---------+----------------+
| id    | int(11)  | NO   | PRI | NULL    | auto_increment |
| name  | char(20) | YES  |     | NULL    |                |
| slary | int(11)  | YES  |     | NULL    |                |
+-------+----------+------+-----+---------+----------------+
3 rows in set (0.00 sec)

 

INSERT INTO SELECT 語句從一個表復制數據，然后把數據插入到一個已存在的表（目標表）中，目標表中任何已存在的行都不會受影響。

語句1：Insert into Table2(field1,field2,…) select value1,value2,… from Table1 where condition;

語句2：Insert into Table2 select * from Table1;

 

說明：1）目標表Table2必須存在，MySQL不會自動創建；

             2）語句1一般用於兩個表結構一致的情況，而語句2用於表結構不一致的情況；

             3）語句1中涉及的field1，field2也必須存在；

             4）若Table2有主鍵且不具備自動增長，則 field1， field2…中必須包括主鍵。

示例：

mysql> create table staff_bak_1 like staff;
Query OK, 0 rows affected (0.05 sec)

mysql> describe staff_bak_1;  //創建了一個與staff數據結構一致的空數據庫，包括主鍵和自動增長等
+-------+----------+------+-----+---------+----------------+
| Field | Type     | Null | Key | Default | Extra          |
+-------+----------+------+-----+---------+----------------+
| id    | int(11)  | NO   | PRI | NULL    | auto_increment |
| name  | char(20) | YES  |     | NULL    |                |
| slary | int(11)  | YES  |     | NULL    |                |
+-------+----------+------+-----+---------+----------------+
3 rows in set (0.01 sec)

mysql> select * from staff_bak_1;
Empty set (0.00 sec)

mysql> insert into staff_bak_1 select * from staff;//將staff內的數據全部復制到剛才創建的空數據庫
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from staff_bak_1;  //結果
+----+----------+-------+
| id | name     | slary |
+----+----------+-------+
|  3 | haofugui | 10000 |
|  4 | guoming  |  3500 |
|  5 | haotian  |  2900 |
+----+----------+-------+
3 rows in set (0.00 sec)

 

mysql> create table staff_bak_2            //創建一個空數據庫
    -> (id int auto_increment primary key,
    -> name char(20));
Query OK, 0 rows affected (0.05 sec)

mysql> describe staff_bak_2;
+-------+----------+------+-----+---------+----------------+
| Field | Type     | Null | Key | Default | Extra          |
+-------+----------+------+-----+---------+----------------+
| id    | int(11)  | NO   | PRI | NULL    | auto_increment |
| name  | char(20) | YES  |     | NULL    |                |
+-------+----------+------+-----+---------+----------------+
2 rows in set (0.01 sec)

mysql> insert into staff_bak_2(name) select name from staff where id!=5; //帶where子句，將指定的記錄復制到新表中。
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from staff_bak_2; //結果
+----+----------+
| id | name     |
+----+----------+
|  1 | haofugui |
|  2 | guoming  |
+----+----------+
2 rows in set (0.00 sec)