--Warning the first line (`realmd` <--- change for your realm database)
DELETE FROM `character` WHERE `account` NOT IN (SELECT `id` FROM `realmd`.`account`);
DELETE FROM auctionhouse WHERE auctioneerguid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_action WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_aura WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_gifts WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_homebind WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_inventory WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_kill WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_pet WHERE owner NOT IN (SELECT guid FROM `character`);
DELETE FROM character_queststatus WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_reputation WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_social WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_spell WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_spell_cooldown WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_ticket WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM character_tutorial WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM corpse WHERE player NOT IN (SELECT guid FROM `character`);
DELETE FROM guild_member WHERE guid NOT IN (SELECT guid FROM `character`);
DELETE FROM item_instance WHERE owner_guid NOT IN (SELECT guid FROM `character`);
DELETE FROM mail WHERE sender NOT IN (SELECT guid FROM `character`);
DELETE FROM character_inventory WHERE item NOT IN (SELECT guid FROM item_instance);
DELETE From character_inventory where item_template not in (SELECT entry from item_template);
DELETE From item_instance where guid not in (SELECT item from character_inventory);