Question

如何将平均值加入此查询？

select t.range, count(*) as num
from
   (select case
       when price < 50000 then '0 - 49K'
       when price >= 50000 and price < 100000 then '50 - 99K'
       when price >= 100000 and price < 200000 then '100 - 199K'
       ...
       as range,
       price
       from table) as t
group by range

我试过

select t.range, count(*) as num, avg(b.val)
from
   (select case
       when price < 50000 then '0 - 49K'
       when price >= 50000 and price < 100000 then '50 - 99K'
       when price >= 100000 and price < 200000 then '100 - 199K'
       ...
       as range,
       price
       from table) as t
    left join table2 b on b.id = t.id
group by range

其他各种微弱的尝试无济于事。

Answer 1

很难说完全不知道“table2”是什么以及它与“table”的关系，但我的第一个想法是在子查询中而不是在它之外进行连接：

select t.range, count(*) as num, avg(t.val)
from
   (select case
       when price < 50000 then '0 - 49K'
       when price >= 50000 and price < 100000 then '50 - 99K'
       when price >= 100000 and price < 200000 then '100 - 199K'
       ...
       as range,
       t1.price,
       b.val
       from table t1
       left join table2 b on b.id = t1.id
) as t
group by range

如何通过查询将join连接到mysql范围案例组？

1 个答案: