Question

我有以下表格，我需要找出总和。

表A


ID Name
1 Jason
2 Peter 
3 Ravi

表B

表C


ID_SEC  Value   Include_Ind
11  100         Y
12  200         Y
13  300         N
21  10          Y
22  20          N 
23  30          N
31  1000        N
32  2000        N
33  3000        N

输出


ID Name  Total  Include_Ind_count [only count when Y]
1 Jason  600     2
2 Peter  60      1
3 Ravi  6000     0

Answer 1

使用：

  SELECT a.id,
         a.name,
         SUM(c.value) AS total
    FROM TABLE_A a
    JOIN TABLE_B b ON b.id = a.id
    JOIN TABLE_C c ON c.id_sec = b.id_sec
GROUP BY a.id, a.name

Answer 2

仅当标志设置为'Y'时计数INCLUDE_IND的技巧是使用CASE（）来测试其值：

SQL> select a.id
  2          , a.name
  3         , sum ( c.val) as total
  4         , count( case when c.include_ind = 'Y' then 1
  5                       else null end ) as inc_ind_cnt
  6  from a
  7          join b on ( b.id = a.id )
  8          join c on ( c.id_sec = b.id_sec )
  9  group by a.name, a.id
 10  order by a.id
 11  /

        ID NAME            TOTAL INC_IND_CNT
---------- ---------- ---------- -----------
         1 Jason             600           2
         2 Peter              60           1
         3 Ravi             6000           0

SQL>

ORDER BY是保证排序顺序所必需的，因为Oracle改变了它在10g中用于GROUP BY操作的算法。

Answer 3

您可以使用内部联接和SUM来获取结果 - 假设你tableC.Value是int字段。否则你需要施展它。

SELECT tabA.id, tabA.name, SUM(tabC.value)
FROM TABLE_A tabA
INNER JOIN TABLE_B tabB ON tabB.id = tabA.id
INNER JOIN TABLE_C tabc ON tabC.id_sec = tabB.id_sec
GROUP BY tabA.id, tabA.name

如何返回此查询的总和？

3 个答案: