如何通过查询将join留在mysql范围案例组中？

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

我试过了

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

---

和其他各种微弱的尝试都没有用。

如果不知道table2是什么以及它与table的关系，很难说清楚，但我的第一个想法是在子查询内部而不是外部执行联接：

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

---

也许我错了，现在很晚了，但我在t定义中没有看到id字段。。。