加入多表并通过列获取mutli bdoup的结果

Question

我想要来自三个表的多列groupby

的结果

表1

| Id| pr_id| c_id| 
|---|------|-----|
| 1 |  33  |  18 |
| 2 |  33  |  19 |
| 3 |  34  |  18 |

表2

|Id| pr_id| qty| 
|--|------|----|
|1 | 33   |  22|
|2 | 33   |  10| 
|3 | 34   |  12|

表3

|c_id| l_id| 
|----|---- |
| 18 |  1  |
| 19 |  2  | 

我想要这样的结果

|total_qty| 1(l_id)| 2(l_id)|pr_id| 
|---------|--------|--------|-----|
| 32      |  22    |   10   |  33 |
| 12      |  12    |   0    |  34 |

Answer 1

使用条件聚合

select t.one + t.two as total_qty, 
       t.*
from
(
  select sum(case when t3.l_id = 1 then t2.qty end) as one,
          sum(case when t3.l_id = 2 then t2.qty end) as two,
          t1.pr_id
   from table3 t3
   join table1 t1 on t1.c_id = t3.c_id
   join table2 t2 on t1.id= t2.id and 
                     t1.pr_id = t2.pr_id
   group by t1.pr_id
) t