รบกวนสอบถามการ Query 3 ตารางด้วยคำสั่ง Group By และ Having ด้วยครับ

SELECT SUM(item_price),SUM(item_qtyin),SUM(item_qtyou)
FROM Item_Price
LEFT JOIN Item_In  ON Item_Price.item_price_number=Item_In.item_price_number
LEFT JOIN Item_Out ON Item_Price.item_price_number=Item_Out.item_price_number
WHERE Item_Price.item_id='A001' AND
Item_In.item_id='A001' AND
Item_Out.item_id='A001'

select
  t1.c1
, t2.c2
, t3.c3
, t4.c4
from ((t1
inner join t2 on t1.something = t2.something)
inner join t3 on t2.something = t3.something)
inner join t4 on t3.something = t4.something

SELECT SUM(DISTINCT item_price),SUM(DISTINCT item_qtyin),SUM(DISTINCT item_qtyou)
FROM Item_Price
LEFT JOIN Item_In  ON Item_Price.item_price_number=Item_In.item_price_number
LEFT JOIN Item_Out ON Item_Price.item_price_number=Item_Out.item_price_number
WHERE Item_Price.item_id='A001' AND
Item_In.item_id='A001' AND
Item_Out.item_id='A001'
GROUP BY Item_Price.item_price_number,Item_In.item_price_number,Item_Out.item_price_number

SELECT DISTINCT
  (SELECT SUM(t1.item_price)FROM Item_Price t1 WHERE t1.item_id='A001' AND t1.item_price_number=Item_Price.item_price_number  GROUP BY t1.item_price_number) item_price,
  (SELECT SUM(t2.item_qtyin)FROM Item_In    t2 WHERE t2.item_id='A001' AND t2.item_price_number=Item_Price.item_price_number GROUP BY t2.item_price_number) item_qtyin,
  (SELECT SUM(t3.item_qtyou)FROM Item_Out   t3 WHERE t3.item_id='A001' AND t3.item_price_number=Item_Price.item_price_number GROUP BY t3.item_price_number) item_qtyin
FROM Item_Price