Question

我在案件中有2个条件，但结果不是我想要的

这是我的代码：

SELECT CASE WHEN count(b.id_canteen) < 2 and status = 'Active' THEN 'Available'
            ELSE 'Full' END as quota, 
       a.id_canteen, 
       name_canteen, 
       count(b.id_counter) as total 
from canteen_A a 
     join canteen_B b  on a.id_canteen=b.id_canteen 
group by a.id_canteen,
         name_canteen,
         status;

这是结果

=================================================
|   quota   | id_canteen | name_canteen | total |
=================================================
| Available | Canteen01   | Canteen A   |   1   |
| Available | Canteen02   | Canteen B   |   1   |
| Full      | Canteen01   | Canteen A   |   1   |
=================================================

和我想要的结果

=================================================
|   quota   | id_canteen | name_canteen | total |
=================================================
| Available | Canteen01   | Canteen A   |   2   |
| Available | Canteen02   | Canteen B   |   1   |
=================================================

这是字段状态

==============================
|   Status   |  id_canteen   |
==============================
| Not Active |   Canteen01   |
|   Active   |   Canteen01   |
|   Active   |   Canteen02   |
==============================

更新：我想要添加条件计数（状态）活动＆lt; 2。我该怎么办？

Answer 1

问题是GROUP BY。您不希望其中包含status。所以，我想：

select (case when count(b.id_canteen) < 2 and
                  sum(case when status = 'Active' then 1 else 0 end) > 0
             then 'Available' 
             else 'Full' 
         end) as quota, 
       a.id_canteen, name_canteen, 
       count(b.id_counter) as total 
from canteen_A a join
     canteen_B b 
     on a.id_canteen = b.id_canteen 
group by a.id_canteen, name_canteen

Answer 2

这会带来什么回报？

SELECT
      X.id_canteen, 
      X.name_canteen, 
      CASE
        WHEN X.total < 2 AND X.status = 'Active' THEN
          'Available'
        ELSE
          'Full'
      END quota
FROM
      (
        SELECT
              a.id_canteen, 
              a.name_canteen,
              b.status
              COUNT(b.id_counter) total 
          FROM
              canteen_A a 
            JOIN
              canteen_B b
                ON a.id_canteen = b.id_canteen
          GROUP BY
              a.id_canteen,
              a.name_canteen,
              b.status
        ) X

以下三个条件

2 个答案: