Question

我有一个问题要问你。我有这个250.000记录的数据库，有2个文本字段，每个字段最多包含300个单词。我想要选择符合某些条件的所有数据并将其放在另一个表中。我想用这个wuery删除那些不满足我条件的录音：

DELETE FROM `cables` WHERE 
`data` NOT LIKE "%BRV%" AND
`data` NOT LIKE "%Venezuela%" AND
`data` NOT LIKE "%Caracas%" AND
`data` NOT LIKE "%Hugo Chavez%" AND
`tags` NOT LIKE "%BRV%" AND
`tags` NOT LIKE "%Venezuela%" AND
`tags` NOT LIKE "%Caracas%" AND
`tags` NOT LIKE "%Hugo Chavez%" AND
`header` NOT LIKE "%BRV%" AND
`header` NOT LIKE "%Venezuela%" AND
`header` NOT LIKE "%Caracas%" AND
`header` NOT LIKE "%Hugo Chavez%" AND
`subject` NOT LIKE "%BRV%" AND
`subject` NOT LIKE "%Venezuela%" AND
`subject` NOT LIKE "%Caracas%" AND
`subject` NOT LIKE "%Hugo Chavez%" AND
`tmp` NOT LIKE "%BRV%" AND
`tmp` NOT LIKE "%Venezuela%" AND
`tmp` NOT LIKE "%Caracas%" AND
`tmp` NOT LIKE "%Hugo Chavez%" AND
`identifier` NOT LIKE "%BRV%" AND
`identifier` NOT LIKE "%Venezuela%" AND
`identifier` NOT LIKE "%Caracas%" AND
`identifier` NOT LIKE "%Hugo Chavez%"

如果每行包含至少一次这些单词，则每行都可以。事情是，自从它执行以来我已经有3个小时了，没有任何事情发生。我已经停止了进程，没有任何事情发生。最终的结果应该有大约14000个录音，我该怎么办？谢谢!!!!

Answer 1

没有发生任何事，因为你停了下来。因此，commit;尚未完成。

您应该将查询拆分为更短的执行时间。

NOT LIKE %%非常贵！（索引，如果有一些没有使用...）

Answer 2

尝试REGEXP，可能会在这里表现得更好。

DELETE FROM `cables` WHERE
  `data` NOT REGEXP 'BRV|Venezuela|Caracas|Hugo Chavez' AND
  `tags` NOT REGEXP 'BRV|Venezuela|Caracas|Hugo Chavez' AND
  `header` NOT REGEXP 'BRV|Venezuela|Caracas|Hugo Chavez' AND
  `subject` NOT REGEXP 'BRV|Venezuela|Caracas|Hugo Chavez' AND
  `tmp` NOT REGEXP 'BRV|Venezuela|Caracas|Hugo Chavez' AND
  `identifier` NOT REGEXP 'BRV|Venezuela|Caracas|Hugo Chavez'

也可以连接（Karolis'建议）

DELETE FROM `cables` WHERE
   CONCAT( `data`, `tags`, `header`, `subject`, `tmp`, `identifier` )
   NOT REGEXP 'BRV|Venezuela|Caracas|Hugo Chavez'

Answer 3

问题是LIKE %text%不会使用全文索引。因此，包含250,000个条目和大量LIKE %%条件的大表将花费很长时间。

您确定需要领先的'％...'吗？否则，您可以尝试使用Boolean search modifier。

Answer 4

为什么不改变条件来选择匹配的记录而不是删除那些不匹配的记录？然后将它们插入另一个表中？这可能会更快，因为即使对于过度使用不喜欢的条件，3小时对于250'000行来说太长了。

INSER INTO `selected_cables`
SELECT * FROM `cables`
WHERE NOT ( 
`data` NOT LIKE "%BRV%" AND
`data` NOT LIKE "%Venezuela%" AND
`data` NOT LIKE "%Caracas%" AND
`data` NOT LIKE "%Hugo Chavez%" AND
`tags` NOT LIKE "%BRV%" AND
`tags` NOT LIKE "%Venezuela%" AND
`tags` NOT LIKE "%Caracas%" AND
`tags` NOT LIKE "%Hugo Chavez%" AND
`header` NOT LIKE "%BRV%" AND
`header` NOT LIKE "%Venezuela%" AND
`header` NOT LIKE "%Caracas%" AND
`header` NOT LIKE "%Hugo Chavez%" AND
`subject` NOT LIKE "%BRV%" AND
`subject` NOT LIKE "%Venezuela%" AND
`subject` NOT LIKE "%Caracas%" AND
`subject` NOT LIKE "%Hugo Chavez%" AND
`tmp` NOT LIKE "%BRV%" AND
`tmp` NOT LIKE "%Venezuela%" AND
`tmp` NOT LIKE "%Caracas%" AND
`tmp` NOT LIKE "%Hugo Chavez%" AND
`identifier` NOT LIKE "%BRV%" AND
`identifier` NOT LIKE "%Venezuela%" AND
`identifier` NOT LIKE "%Caracas%" AND
`identifier` NOT LIKE "%Hugo Chavez%")

MYSQL查询执行时间

4 个答案: