加入 前 汇总：
SELECt i.id as id, i.title as title, ip.paths, null as photos, ico.characteristics_arrayFROM items i LEFT JOIN (SELECt ip.item_id, array_agg( ip.path) as paths FROM item_photos ip GROUP BY ip.item_ID ) ip ON ip.id = i.item_id LEFT JOIN (SELECt ico.item_id, array_agg(array [ico.characteristic_id, ico.characteristic_option_id, ico.numeric_value] ) as characteristics_array FROM items_characteristics ico GROUP BY ico.item_id ) ico ON ico.item_id = i.id
