如何连接两个表来计算查询位置

Question

我有两张桌子

表1：ppl

Cust No.|    sex
--------| -------
10      | M
13      | F
12      | M
19      | F
20      | M
22      | M
34      | F

表2：hobbies

Cust No. |  Hobby
---------| ---------
10       | Movies
10       | Hiking
10       | Programming
12       | Biking
12       | Movies
12       | Reading
19       | Biking
20       | Reading
22       | Movies
34       | Flying
22       | Biking

我正试图从表格中以DESC的顺序找到按男/女分布最受欢迎的爱好。

我已经编写了查询以找到DESC订单

中最受欢迎的爱好

select Hobby, count(*)
from hobbies
group by Hobby

问题

如何将此与ppl表格相关联，然后通过M / F为每个表格进行分配？

请注意，我希望最受欢迎的爱好是DESC顺序。首先，我需要最受欢迎的爱好，然后将其分解为M / F

基于上述设置的结果将是：

Hobby        |  M   | F
-------------| -----|----
Movies       | 3    | 0
Hiking       | 1    | 0
Programing   | 1    | 0
Biking       | 2    | 1
Reading      | 2    | 0
Flying       | 0    | 1

Answer 1

这是一个带有join的条件聚合查询：

select h.Hobby,
       sum(case when gender = 'F' then 1 else 0 end) as females,
       sum(case when gender = 'M' then 1 else 0 end) as males
from hobbies h join
     people p
     on h.custno = p.custno
group by h.Hobby
order by count(*) desc;