用某种条件提取数据

Question

我需要一些帮助。请参考下图： -

我怎么能通过SQL这样做？

使用以下SQL： -

Select Size, Grade, sum(Qty) Qty, Price, sum(Qty*Price) Value
From TableA
Left outer join 
TableB 
on a.Size=b.Size and a.Grade=b.Grade

由于

Answer 1

你可以这样做

WITH agg_cte AS
(
  SELECT size, 
         SUM(CASE WHEN grade = '1' THEN qty END) qty1,
         SUM(CASE WHEN grade = '2' THEN qty END) qty2
    FROM tableb
   GROUP BY size
), totals AS 
(
  SELECT size, qty1, 
         CASE WHEN qty2 > qty1 * 0.2 THEN qty1 * 0.2 ELSE qty2 END qty2,
         CASE WHEN qty2 > qty1 * 0.2 THEN qty2 - qty1 * 0.2 ELSE 0 END qty2e
    FROM agg_cte
)
SELECT p.size, p.grade, 
       CASE p.grade WHEN '1'  THEN qty1
                    WHEN '2'  THEN qty2
                    WHEN '2E' THEN qty2e
       END qty,
       p.price,
       CASE p.grade WHEN '1'  THEN qty1
                    WHEN '2'  THEN qty2
                    WHEN '2E' THEN qty2e
       END * p.price value
FROM TableA p JOIN totals t
    ON p.size = t.size

输出：

|  SIZE | GRADE | QTY | PRICE | VALUE |
|-------|-------|-----|-------|-------|
| 10/12 |     1 |   5 |  2.39 | 11.95 |
| 10/12 |     2 |   1 |  1.79 |  1.79 |
| 10/12 |    2E |   3 |  1.55 |  4.65 |

这是 SQLFiddle 演示