根据状态分组，然后根据其类别ID统计其产品和总数

Question

我有一个包含产品 ID、类别 ID 和产品状态的表格。

+---------+-------------+-------------+
|   id    |   cat_id    |   status    |
+---------+-------------+-------------+
|    1    |     1       |      1      |
|    2    |     1       |      1      |
|    3    |     2       |      1      |
|    4    |     2       |      0      |
|    5    |     1       |      0      |
|    6    |     2       |      0      |
+---------+-------------+-------------+

如何根据其状态进行分组，然后根据其类别 ID 计算其产品和总数？我期待这样：

+---------+-------------+-------------+-----------+
|  cat_id |  published  | unpublished |   totals  |
+---------+-------------+-------------+-----------+
|    1    |     2       |      1      |     3     |
|    2    |     1       |      2      |     3     |
+---------+-------------+-------------+-----------+

哪里status=1是published和status=0是unpublished。

Answer 1

您需要使用 sum(case) 进行条件聚合：

select cat_id,
   sum(case when status = 1 then 1 else 0 end) as published,  -- only count status 1
   sum(case when status = 0 then 1 else 0 end) as unpublished,-- only count status 0
   count(*) as totals
from tab
group by cat_id

编辑：

我的水晶球显然坏了，但现在已经修好了:-)

如果您只需要计算每个 product_id 一次，您可以使用它：

select cat_id,
   count(distinct case when status = 1 then product_id end) as published,  -- only count status 1
   count(distinct case when status = 0 then product_id end) as unpublished,-- only count status 0
   count(distinct product_id) as totals
from tab join whatever...
group by cat_id