我有两张桌子：需求表＆amp;库存表。
第一张表：所需数量
| Ship From | Material | Req Date | Req Quantity | Fulfill (Y/N)? |
|-----------|----------|-----------|--------------|----------------|
| 21 | Mat1 | 7/1/2018 | 46 | |
| 21 | Mat1 | 8/19/2018 | 33 | |
| 21 | Mat1 | 9/2/2018 | 99 | |
| 21 | Mat1 | 9/2/2018 | 4 | |
| 106 | Mat1 | 9/16/2018 | 92 | |
| 106 | Mat1 | 8/19/2018 | 126 | |
| 457 | Mat2 | 8/19/2018 | 126 | |
| 457 | Mat2 | 9/10/2018 | 126 | |
| 457 | Mat2 | 9/10/2018 | 126 | |
| 457 | Mat2 | 9/10/2018 | 24 | |
| 478 | Mat2 | 9/2/2018 | 52 | |
| 478 | Mat2 | 9/10/2018 | 73 | |
| 478 | Mat2 | 9/10/2018 | 18 | |
| 478 | Mat2 | 9/16/2018 | 30 | |
第二张表：可用库存
----------- ---------- -------------------- ---------------
Ship From Material Inv Available Date Available Qty
----------- ---------- -------------------- ---------------
21 Mat1 6/15/2018 46
21 Mat1 6/15/2018 33
21 Mat1 7/2/2018 99
21 Mat1 10/2/2018 4
106 Mat1 10/16/2018 92
106 Mat1 7/19/2018 126
457 Mat2 8/19/2018 126
457 Mat2 8/10/2018 126
478 Mat2 9/16/2018 30
478 Mat2 10/2/2018 52
需要在Inv可用日期或之前检查第二个表格中是否有足够的库存（总和（可用数量））并在table1上标记我们是否可以履行订单。
请注意，对于表1中履行的订单，我们需要减少表2中的数量总和。
我在table1中有70k行，在table2中有600k行。
Select
Y1.Material,
Y1.[Order Qty],
Y1.[Ship From],
Y1.[Code Date] as Req_date,
I1.[Code Date] as Inv_date,
(SELECT CASE WHEN (Select SUM(I1.Quantity) as sum_qty FROM YOTC_ALL Y1, Inventory I1 WHERE Y1.Material = I1.Material AND Y1.[Ship From] = I1.[Ship From] AND
Y1.[Code Date] > = I1.[Code Date]) > Y1.[Order Qty]) THEN "Y" ELSE "N"
FROM
YOTC_ALL Y1,
Inventory I1
WHERE
Y1.Material = I1.Material AND
Y1.[Ship From] = I1.[Ship From] AND
Y1.[Code Date] > = I1.[Code Date]
GROUP BY
I1.[Code Date],
Y1.Material,
Y1.[Order Qty],
Y1.[Ship From],
Y1.[Code Date];
我已经尝试过上述查询，但似乎无法让它发挥作用。请帮助!!!