Query failed: SELECT comments.id, comments.page_tag, comments.time, comments.comment, comments.user FROM wikka_comments AS comments LEFT JOIN wikka_comments AS c2 ON comments.page_tag = c2.page_tag AND comments.id < c2.id WHERE c2.page_tag IS NULL ORDER BY time DESC LIMIT 50 (The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay)