MYSQL查詢執行時間

Question

我有一個問題問你。 我的數據庫有250.000條記錄，其中2個文本字段最多包含300個單詞。 我想選擇所有符合某些條件的數據，然后將其放在另一個表中。 我想刪除這些不符合我的條件的錄音：

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%"

如果每一行至少包含這些單詞中的任何一個，則可以。 事實是，自執行以來，我已經有3個小時了，什么也沒發生。 我已經停止了該過程，但沒有任何反應。 最終結果應該有大約14000張錄音，我該怎么辦？ 謝謝！！！！

Answer 1

什么都沒發生，因為您停止了它。 因此， commit; 尚未完成。

您應該拆分查詢以縮短執行時間。

NOT LIKE %%非常非常昂貴！！！ （索引，如果有一些未使用...）

Answer 2

嘗試REGEXP ，在這里可能會更好。

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'

也可以串聯使用（Karolis的建議）

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

Answer 3

問題在於， LIKE %text%將不會使用全文索引。 因此，包含250.000個條目和很多LIKE %%標准的大型表將花費很長時間。

您確定需要前導的“％...”嗎？ 否則，您可以嘗試使用布爾搜索修飾符 。

Answer 4

為什么不反轉條件以選擇匹配的記錄，而不是刪除不匹配的記錄？ 然后將它們插入另一個表？ 這可能會更快一些，因為即使過度使用非常規條件也要3個小時，對於250'000行來說太長了。

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%")