相關嵌套查詢的查詢優化（SQL Server）

Question

在相關的嵌套查詢中有WHERE子句，或者在外部查詢中只有WHERE子句，性能會好壞多少？例如：下面的嵌套查詢定義price_key，但外部查詢有一個price_key引用，也外查詢的WHERE語句

INNER JOIN (
      SELECT inv.item_key, s.price_key, MAX(inv.last_receive_cost/inv.last_receive_units_case) AS [unit_cost] 
      FROM inventory inv 
        INNER JOIN stores s on inv.location_key = s.store_key 
      WHERE inv.on_hand_inventory_qty > 0 
        AND inv.last_receive_cost > 0 
        AND inv.last_receive_units_case > 0 
        AND s.price_key = (29) 
      GROUP BY inv.item_key, s.price_key 
) t ON r.item_key = t.item_key and r.price_key = t.price_key 

Answer 1

INNER JOIN (
      SELECT inv.item_key --, s.price_key 
       , MAX(inv.last_receive_cost/inv.last_receive_units_case) AS [unit_cost] 
      FROM inventory inv 
        INNER JOIN stores s on inv.location_key = s.store_key 
      WHERE inv.on_hand_inventory_qty > 0 
        AND inv.last_receive_cost > 0 
        AND inv.last_receive_units_case > 0 
        AND s.price_key = 29 
      GROUP BY inv.item_key 
-- , s.price_key 
) t ON r.item_key = t.item_key 
    and r.price_key = 29