错误消息表明 DISTINCT 只允许在一列[组合]上使用，但您可以尝试两列， color_key & id . 解决方法是两个选择，然后一个连接：

select
   t1.upload_key,
   t1.upload_time,
   t1.max_color_fk,
   t1.color_count,
   t2.toy_count
from
 (
   select 
      upload_key, 
      max(my_timestamp) as upload_time, 
      max(color_key) as max_color_fk, 
      count(distinct color_key) as color_count
   from upload_table 
   group by upload_key
 ) as t1
join
 (
   select 
      upload_key
      count(distinct id) as toy_count 
   from upload_table 
   group by upload_key
 ) as t2
on t1. upload_key = t2.upload_key