SELECT count(*)
FROM contacts_lists
JOIN plain_contacts
ON contacts_lists.contact_id = plain_contacts.contact_id
JOIN contacts
ON contacts.id = plain_contacts.contact_id
WHERE plain_contacts.has_email
AND NOT contacts.email_bad
AND NOT contacts.email_unsub
AND contacts_lists.list_id =67339
如何优化这个查询...你能解释一下吗?
EXPLAIN ANALYZE
)。 - user330315