NPCs have a loottable ID, loottables have lootdrops, lootdrops have items.
So to find what items drop on a certain NPC all you need to do is run this query (# is your NPC ID).
Code:
SELECT
items.*
FROM
items
INNER JOIN lootdrop_entries ON items.id = lootdrop_entries.item_id
INNER JOIN loottable_entries ON lootdrop_entries.lootdrop_id = loottable_entries.lootdrop_id
INNER JOIN npc_types ON loottable_entries.loottable_id = npc_types.loottable_id
WHERE
npc_types.id = #;