分组后的条件求和

select sum(if(status=1,amount,0)) from orders group by created_at;

select sum(amount), created_at, status from orders group by created_at,status;

有种做大学作业的感觉。。。

select 
  t1.created_at, 
  sum(t1.total_0) as 'amount_0', 
  sum(t1.total_1) as 'amount_1' 
from 
  (
    select 
      t.created_at, 
      (
        case t.status when 1 then t.amount end
      ) as 'total_0', 
      (
        case t.status when 2 then t.amount end
      ) as 'total_1' 
    from 
      (
        select  created_at, status, sum(amount) as 'amount'  from   orders  group by created_at, status
      ) as t
  ) as t1 
group by  created_at

更简洁的

select  created_at,
sum(case status when 1 then amount end) as 'total_1',
sum(case status when 0 then amount end) as 'total_2'
from   orders  group by created_at

数据量大的话，这种查询很慢，建议用内存换速度，外加一个统计表