MySQL第五天

 

复制表结构

 1 #从src_table复制到dst_table
 2  CREATE TABLE dst_table LIKE src_table;
 3 
 4 #另外一种方法
 5   CREATE TABLE dst_table SELECT * FROM src_table WHERE 0;
 6 
 7 #第一种方法比第二种方法简单实用效率高
 8 
 9 
10 #复制表中数据
11 #完全复制src_table
12 CREATE TABLE det_table SELECT * FROM src_table;
13 
14 #复制其中两列
15 CREATE TABLE det_table SELECT a,b FROM src_table;
16 
17 #也可以先创建表，然后再进行复制
18 SELECT INTO dst_table(a1,b1) SELECT a2,b2 FROM src_table;
19 

查看、更改当前表的引挚

#第一中方法，非常实用，但是很长比较麻烦，
mysql> SELECT ENGINE FROM INFORMATION_SCHEMA.TABLES
    -> WHERE TABLE_SCHEMA = 'cookbook' AND TABLE_NAME = 'mail';
+--------+
| ENGINE |
+--------+
| MyISAM |
+--------+
1 row in set (0.00 sec)

#第二种方法
mysql> SHOW TABLE STATUS LIKE 'mail'\G
*************************** 1. row ***************************
           Name: mail
         Engine: MyISAM
        Version: 10
     Row_format: Fixed
           Rows: 16
 Avg_row_length: 73
    Data_length: 1168
Max_data_length: 20547673299877887
   Index_length: 2048
      Data_free: 0
 Auto_increment: NULL
    Create_time: 2010-08-12 21:50:25
    Update_time: 2010-08-12 21:50:25
     Check_time: NULL
      Collation: utf8_general_ci
       Checksum: NULL
 Create_options:
        Comment:
1 row in set (0.00 sec)


#第三种方法
mysql> SHOW CREATE TABLE mail \G
*************************** 1. row ***************************
       Table: mail
Create Table: CREATE TABLE `mail` (
  `t` datetime DEFAULT NULL,
  `srcuser` char(8) CHARACTER SET latin1 DEFAULT NULL,
  `srchost` char(20) CHARACTER SET latin1 DEFAULT NULL,
  `dstuser` char(8) CHARACTER SET latin1 DEFAULT NULL,
  `dsthost` char(20) CHARACTER SET latin1 DEFAULT NULL,
  `size` bigint(20) DEFAULT NULL,
  KEY `t` (`t`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8
1 row in set (0.00 sec)


#修改表的引挚，但是修改会非常耗资源，小心
#把表mail的引挚修改为InnoDB
mysql> ALTER TABLE mail ENGINE = InnoDB;
Query OK, 16 rows affected (0.02 sec)
Records: 16  Duplicates: 0  Warnings: 0