语法:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
[(create_definition,...)]
[table_options] [select_statement]
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
[(] LIKE old_tbl_name [)];
测试过程:
原数据表:
mysql> show create table test_order \G *************************** 1. row *************************** Table: test_order Create Table: CREATE TABLE `test_order` ( `pay_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, `origin` int(10) DEFAULT NULL, `team_id` int(11) DEFAULT NULL, `state` int(11) DEFAULT NULL, KEY `team_id` (`team_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 1 row in set (0.00 sec)
mysql> create table cc select * from test_order; Query OK, 9900 rows affected (0.11 sec) Records: 9900 Duplicates: 0 Warnings: 0
mysql> create table dd like test_order; Query OK, 0 rows affected (0.22 sec)
查看数据:
mysql> select * from cc limit 2; +---------------------+--------+---------+-------+ | pay_time | origin | team_id | state | +---------------------+--------+---------+-------+ | 2011-06-22 18:04:47 | 10 | 100 | 100 | | 2011-06-22 18:04:47 | 10 | 100 | 101 | +---------------------+--------+---------+-------+ 2 rows in set (0.00 sec)
mysql> select * from dd; Empty set (0.00 sec)
结果:cc表中数据与原表test_order中的一致,dd表中无数据
查看表结构:
mysql> show create table cc \G *************************** 1. row *************************** Table: cc Create Table: CREATE TABLE `cc` ( `pay_time` timestamp NOT NULL DEFAULT ‘0000-00-00 00:00:00‘, `origin` int(10) DEFAULT NULL, `team_id` int(11) DEFAULT NULL, `state` int(11) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8 1 row in set (0.00 sec)
mysql> show create table dd \G *************************** 1. row *************************** Table: dd Create Table: CREATE TABLE `dd` ( `pay_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, `origin` int(10) DEFAULT NULL, `team_id` int(11) DEFAULT NULL, `state` int(11) DEFAULT NULL, KEY `team_id` (`team_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 1 row in set (0.00 sec)
结果:cc表中,原表中的索引消失了;dd表与原表一致
结论:
create table select 会将原表中的数据完整复制一份,但表结构中的索引会丢失。
create table like 只会完整复制原表的建表语句,但不会复制数据
时间: 2024-11-05 12:13:05