MySQL复制表3种方式
本节目标
1.掌握MySQL复制表的几种方式
复制表，即备份表，给我们在操作表的时候，留一条后路
复制表的三种方式：
1.只复制表结构
create table tableName like someTable;
2.只复制表数据
create table tableName select * from someTable;
3.复制表结构+数据
create table tableName like someTable;
insert into tableName select * from someTable;
实战环节：
0.前期准备
创建一个t1表和索引
create table t1(
id int not null auto_increment primary key,
name varchar(50)
);
插入两条数据
insert into t1(name) values('张三');
insert into t1(name) values('李四');
假如索引建在名字上
create index idx_name on t1(name);
结果如下：
mysql> create table t1(
-> id int not null auto_increment primary key,
-> name varchar(50)
-> );
Query OK, 0 rows affected (5.73 sec)
mysql> insert into t1(name) values('张三');
Query OK, 1 row affected (0.54 sec)
mysql> insert into t1(name) values('李四');
Query OK, 1 row affected (0.26 sec)
mysql> create index idx_name on t1(name);
Query OK, 0 rows affected (2.34 sec)
Records: 0 Duplicates: 0 Warnings: 0
查看索引
show index from t1;
mysql> show index from t1\G;
*************************** 1. row ***************************
Table: t1
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name: id
Collation: A
Cardinality: 2
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
Visible: YES
Expression: NULL
*************************** 2. row ***************************
Table: t1
Non_unique: 1
Key_name: idx_name
Seq_in_index: 1
Column_name: name
Collation: A
Cardinality: 2
Sub_part: NULL
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
Index_comment:
Visible: YES
Expression: NULL
2 rows in set (0.08 sec)
ERROR:
No query specified
正题：
1.只复制表结构
create table t2 like t1;
mysql> create table t2 like t1;
Query OK, 0 rows affected (2.77 sec)
使用select * from t2;
发现数据真的没复制过来
mysql> select * from t2;
Empty set (0.17 sec)
索引和表结构如何呢？复制过来没有？我们看一看
show index from t2;
desc t2;
show create table t2;
mysql> show index from t2\G;
*************************** 1. row ***************************
Table: t2
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name: id
Collation: A
Cardinality: 0
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
Visible: YES
Expression: NULL
*************************** 2. row ***************************
Table: t2
Non_unique: 1
Key_name: idx_name
Seq_in_index: 1
Column_name: name
Collation: A
Cardinality: 0
Sub_part: NULL
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
Index_comment:
Visible: YES
Expression: NULL
2 rows in set (0.01 sec)
ERROR:
No query specified
mysql> desc t2;
+-------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(50) | YES | MUL | NULL | |
+-------+-------------+------+-----+---------+----------------+
2 rows in set (1.44 sec)
mysql> show create table t2;
+-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| t2 | CREATE TABLE `t2` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `idx_name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
+-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.05 sec)
我们发现，索引和表结构确确实实复制过来了。
2.仅复制数据
create table t3 select * from t1;
mysql> create table t3 select * from t1;
Query OK, 2 rows affected (1.15 sec)
Records: 2 Duplicates: 0 Warnings: 0
查看表结构，发现主键索引并没有复制过来
mysql> show create table t3;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------+
| t3 | CREATE TABLE `t3` (
`id` int(11) NOT NULL DEFAULT '0',
`name` varchar(50) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.05 sec)
查看索引
mysql> show index from t3;
Empty set (0.05 sec)
查看表数据，发现已经复制成功
mysql> select * from t3;
+----+------+
| id | name |
+----+------+
| 1 | 张三 |
| 2 | 李四 |
+----+------+
2 rows in set (0.00 sec)
3.完整复制
步骤一：复制表结构create table t4 like t1;
步骤二：向新表插入数据insert into t4 select * from t1;
mysql> create table t4 like t1;
Query OK, 0 rows affected (0.82 sec)
mysql> insert into t4 select * from t1;
Query OK, 2 rows affected (0.21 sec)
Records: 2 Duplicates: 0 Warnings: 0
查看建表语句
show create table t4;
查看索引
show index from t4;
查看数据
select * from t4;
结果如下：
mysql> show create table t4\G;
*************************** 1. row ***************************
Table: t4
Create Table: CREATE TABLE `t4` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `idx_name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
1 row in set (0.00 sec)
ERROR:
No query specified
mysql> show index from t4\G;
*************************** 1. row ***************************
Table: t4
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name: id
Collation: A
Cardinality: 2
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
Visible: YES
Expression: NULL
*************************** 2. row ***************************
Table: t4
Non_unique: 1
Key_name: idx_name
Seq_in_index: 1
Column_name: name
Collation: A
Cardinality: 2
Sub_part: NULL
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
Index_comment:
Visible: YES
Expression: NULL
2 rows in set (0.03 sec)
ERROR:
No query specified
mysql> select * from t4;
+----+------+
| id | name |
+----+------+
| 1 | 张三 |
| 2 | 李四 |
+----+------+
2 rows in set (0.00 sec)
全部复制过来了