mysql - 根据一定条件SQL计算各组贡献百分比

Question

我想计算 2 个组的“数量”贡献百分比，其中“客户 ID”出现多次的组 1 和“客户 ID”出现一次的组 2。例如:

|ID | OrderID   |Quantity
|---|--------   |-----
|1  |10248      |12
|2  |10248      |10 
|3  |10248      |5 
|4  |10249      |9
|5  |10249      |40
|6  |10250      |10

-----进入-----

OrderID |Quantity
10248   |27
10249   |49
10250   |10

-----最终进入-----

Group    % tot Quantity
1         12%   <--- Just OrderID 10250 since it has only 1 order
2         88%

Answer 1

select
   100.0 * sum(case when cnt = 1  then sumQty else 0 end) / sum(sumQty) as "single Order"
  ,100.0 * sum(case when cnt <> 1 then sumQty else 0 end) / sum(sumQty) as "multiple Orders"
from
 (
    select 
       OrderID
      ,sum(Quantity) as sumQty
      ,count(*) as cnt
    from myTable
    group by OrderId
 ) as dt