Home Database Mysql Tutorial mysql 临时表 cann''t reopen解决方案

mysql 临时表 cann''t reopen解决方案

Jun 07, 2016 pm 05:55 PM
mysql Temporary tables

MySql关于临时表cann't reopen的问题,本文将提供详细的解决方案,需要了解的朋友可以参考下

当你创建临时表的时候,你可以使用temporary关键字。如:
代码如下:
create temporary table tmp_table(name varchar(10) not null,passwd char(6) not null);


代码如下:
create temporary table if not exists sp_output_tmp engine= memory select …from … where ID=current_id;

临时表只在当前连接可见,当这个连接关闭的时候,会自动drop。这就意味着你可以在两个不同的连接里使用相同的临时表名,并且相互不会冲突,或者使用 已经存在的表,但不是临时表的表名。(当这个临时表存在的时候,存在的表被隐藏了,如果临时表被drop,存在的表就可见了)。创建临时表你必须有
create temporary table 权限。
下面几点是临时表的限制
1、临时表只能用在 memory,myisam,merge,或者innodb
2、临时表不支持mysql cluster(簇)
3、在同一个query语句中,你只能查找一次临时表。例如:下面的就不可用
代码如下:
mysql> SELECT * FROM temp_table, temp_table AS t2;
ERROR 1137: Can't reopen table: 'temp_table'

mysql bug地址:http://bugs.mysql.com/bug.php?id=10327
如果在一个存储函数里,你用不同的别名查找一个临时表多次,或者在这个存储函数里用不同的语句查找,这个错误都会发生。
4、show tables 语句不会列举临时表
你不能用rename来重命名一个临时表。但是,你可以alter table代替:
代码如下:
mysql>ALTER TABLE orig_name RENAME new_name;

临时表用完后要记得drop掉:
代码如下:
DROP TEMPORARY TABLE IF EXISTS sp_output_tmp;

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