Question

我正在使用Oracle数据库，我遇到了从2个结果集中获得一个结果的问题。

我有表CASES

Create table cases (ID varchar(1), date_entered date, sub_category varchar (5));

insert into cases (id, date_entered, sub_category)
values('1', to_date('2012/05/03','yyyy/mm/dd'),'Temp1');
insert into cases (id, date_entered, sub_category)
values('2', to_date('2012/06/01','yyyy/mm/dd'),'Temp2');
insert into cases (id, date_entered, sub_category)
values('3', to_date('2012/03/15','yyyy/mm/dd'),'Temp3');
insert into cases (id, date_entered, sub_category)
values('4', to_date('2012/03/01','yyyy/mm/dd'),'Call1');
insert into cases (id, date_entered, sub_category)
values('5', to_date('2012/03/08','yyyy/mm/dd'),'Call2');
insert into cases (id, date_entered, sub_category)
values('6', to_date('2012/02/20','yyyy/mm/dd'),'Call2');

需要按子类别计算记录，按月计算一次计数包括sub_category：Temp1，Temp2，Temp3 其他计数包括sub_category：Call1，Call2，Call3

我做了query1：

With skills
    AS 
    ( 
          Select sub_category, 
                 date_entered,
                 extract(MONTH FROM cases.date_entered) as month_entered, 
                 count (*)
          from cases 
          where 
                SUB_CATEGORY IN('Temp1', 'Temp2', 'Temp3')


          group by cases.sub_category, cases.date_entered
          order by to_char(cases.date_entered,'MM')
    )

    select  s.month_entered, 
            count(*)as skill_count
            from skills s

    group by s.month_entered
    ORDER BY CAST(s.month_entered AS INTEGER) ASC

结果：

MONTH_ENTERED   SKILL_COUNT
3               1
5               1
6               1

和查询2：

With training
AS 
( 
      Select sub_category, 
             date_entered,
             extract(MONTH FROM cases.date_entered) as month_entered, 
             count (*)
      from cases 
      where 
            SUB_CATEGORY IN('Call1', 'Call2', 'Call3')


      group by cases.sub_category, cases.date_entered
      order by to_char(cases.date_entered,'MM')
)

select  t.month_entered, 
        count(*)as training_count
        from training t

group by t.month_entered
ORDER BY CAST(t.month_entered AS INTEGER) ASC

结果：

MONTH_ENTERED   TRAINING_COUNT
2                1
3                2

我从这两个查询中得到的结果是：

MONTH_ENTERED   SKILL_COUNT  TRAINING_COUNT
    2               0            1
    3               1            2
    5               1            0
    6               1            0

试过联盟并离开了加入，但没有什么能给我这个结果......

这是sqlfiddle示例http://sqlfiddle.com/#!4/504cd/31

请帮助，紧急，我被困住了！提前谢谢

桂贵的回答被接受了。你能帮我解决这个问题还是我需要新的问题？如果我想在一年中的所有其他月份显示零，哪些不在表格中，我应该在查询中添加什么？

Answer 1

我认为您可以将查询大幅简化为：

      Select extract(MONTH FROM cases.date_entered) as month_entered, 
             sum(case when SUB_CATEGORY IN('Temp1', 'Temp2', 'Temp3') then 1 else 0 end) as Skill_Count,
             sum(case when SUB_CATEGORY IN('Call1', 'Call2', 'Call3') then 1 else 0 end) as Skill_Count,
      from cases 
      group by extract(MONTH FROM cases.date_entered)
      order by extract(MONTH FROM cases.date_entered)

Answer 2

SELECT
  EXTRACT(MONTH FROM CASES.DATE_ENTERED) AS MONTH_ENTERED,
  COUNT (CASE WHEN SUB_CATEGORY IN('Temp1', 'Temp2', 'Temp3') THEN 1 END) SKILL_COUNT,
  COUNT (CASE WHEN SUB_CATEGORY IN('Call1', 'Call2', 'Call3') THEN 1 END) TRAINING_COUNT
FROM CASES
GROUP BY EXTRACT(MONTH FROM DATE_ENTERED)
ORDER BY MONTH_ENTERED ASC

Oracle 11g：如何合并两个结果集

2 个答案: