Mysql:如果存在则重命名表

Question

这个 DROP TABLE IF EXISTS 有效，可惜 RENAME TABLE IF EXISTS 无效。

谁能为此查询提出解决方案？

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'IF EXISTS video_top_day TO video_top_day_for_delete' at line 1

查询:

RENAME TABLE IF EXISTS video_top_day TO video_top_day_for_delete

Answer 1

我已经设法执行了一个代码，该代码始终有效并且在表不存在时不会产生错误:

SELECT Count(*)
INTO @exists
FROM information_schema.tables 
WHERE table_schema = [DATABASE_NAME]
    AND table_type = 'BASE TABLE'
    AND table_name = 'video_top_day';

SET @query = If(@exists>0,
    'RENAME TABLE video_top_day TO video_top_day_for_delete',
    'SELECT \'nothing to rename\' status');

PREPARE stmt FROM @query;

EXECUTE stmt;

当您不想手动替换[DATABASE NAME]时，您可以使用以下变量

SELECT DATABASE() INTO @db_name FROM DUAL;