使用主键索引在MySQL中删除行

Question

I am trying to delete many rows using primary key search.

eg

DELETE FROM t1 WHERE t1.pid IN (SELECT pid FROM ...);

Here pid is primary key of table t1 but it is not using index in case of delete.
The inner query is returning too many rows so the whole query is taking too much time as outer one is not using index.

How can I delete those rows faster?

Answer 1

You should avoid the subquery, but use JOIN instead:

DELETE t1
FROM t1 INNER JOIN t2 ON t1.pid = t2.pid
[WHERE .....]

Naturally t2 is the table you're getting pid from in your subquery; consider you can also add the WHERE clause to limit selected (and so deleted) pids...
Also consider that pid column on t2 table should be indexed to speed up query...