Oracle SQL 按多个字段计数和分组答案

【问题标题】：Oracle SQL count and group by multiple fieldsOracle SQL 按多个字段计数和分组
【发布时间】：2018-08-17 04:37:23
【问题描述】：

我能够得到合并两个表的数据来得到下表。

+------------+------+--------+--------+------------+------------+
| Group Name | Type | Manger | Status | ControlOne | ControlTwo |
+------------+------+--------+--------+------------+------------+
| Group A    |    1 |      1 | finish |          2 |          2 |
| Group A    |    2 |      1 | open   |          0 |          2 |
| Group A    |    1 |      1 | finish |          0 |          0 |
| Group A    |    1 |      2 | finish |          2 |          0 |
| Group B    |    1 |      1 | open   |          2 |          0 |
| Group B    |    1 |      2 | open   |          2 |          2 |
| Group B    |    2 |      2 | open   |          0 |          2 |
| Group B    |    2 |      1 | finish |          0 |          0 |
| Group B    |    1 |      1 | open   |          2 |          0 |
+------------+------+--------+--------+------------+------------+

现在我需要根据 GroupName/ Type 和 Manager 获取总计数，以使每个组的输出格式如下：

+------------+------+-------------------------------------------------+--------------------------------------------+------------------------------+----------------------------+
| Group Name | Type |                 Manager1Finish                  |                Manager1Open                |        Manager2Finish        |        Manager2Open        |
+------------+------+-------------------------------------------------+--------------------------------------------+------------------------------+----------------------------+
| Group A    |    1 | 2(count of finish by Group A, manager1, type 1) | 0(count of open Manager1, Type 1, Group A) | 1(count of finish Manager 2) | 0(count of open manager 2) |
| Group A    |    2 | 0                                               | 1                                          | 0                            | 0                          |
+------------+------+-------------------------------------------------+--------------------------------------------+------------------------------+----------------------------+

请您帮忙看看如何实现这个目标？

【问题讨论】：

您可以尝试使用 oracle 的窗口函数，例如 count(*) over (partition by some_column)，详情请参阅 this

标签： sql oracle count grouping

【解决方案1】：

尝试使用 CASE WHEN：

  SELECT GroupName,
         TYPE,
         COUNT (CASE
                   WHEN     Manager = 1
                        AND status = 'Finish'
                   THEN
                      1
                END)
            AS Manager1Finish,
         COUNT (CASE
                   WHEN     Manager = 1
                        AND status = 'Open'
                   THEN
                      1
                END)
            AS Manager1Open,
         COUNT (CASE
                   WHEN     Manager = 2
                        AND status = 'Finish'
                   THEN
                      1
                END)
            AS Manager2Finish,
         COUNT (CASE
                   WHEN     Manager = 2
                        AND status = 'Open'
                   THEN
                      2
                END)
            AS Manager2Open
    FROM tablename
GROUP BY GroupName, TYPE

【讨论】：

【解决方案2】：

select [group], [type],
sum(case when manager=1 and status='finish' then 1 else 0 end) as m1finish,
sum(case when manager=1 and status='open' then 1 else 0 end) as m1open,
sum(...etc...)
from mytable
group by [group],[type]

【讨论】：