如何优化循环批量删除行

Question

我仍在学习并试图理解SQL中的内容。我有一个脚本，可以像这样批量删除：

while rows_were_deleted:
    DELETE FROM some_table WHERE id IN (SELECT id FROM deletes_table) LIMIT 1000

这很慢。我首先想到的是，SELECT id FROM deletes_table花费了很长时间，因为deletes_table有数千行。所以我尝试了类似的东西

while rows_were_deleted:
    ids_to_delete = SELECT id FROM deletes_table
    for delete_id in ids_to_deletes:
        DELETE FROM some_table WHERE id = delete_id LIMIT 1000

这甚至更慢。我猜是因为还有更多的操作。这样做的最佳方法是什么？

Answer 1

while rows_were_deleted:
    DELETE FROM some_table WHERE id IN (SELECT id FROM deletes_table) LIMIT 1000

您也可以尝试向select id from deletes_tables添加限制。