mysql - 如何将 MySql 联合查询的结果从 2 列拆分为 4

Question

我正在执行这个 mysql 查询

select
    merchant_id, count(*)
from
    OrderDetails
where
    OrderDetails.delivery_date between '2019-07-24 00:00:00' and '2019-11-25 23:59:59' 
group by
    merchant_id

union all

select
    merchant_id, count(order_status_id)
from
    OrderDetails
where
    OrderDetails.delivery_date BETWEEN '2019-07-24 00:00:00' and '2019-11-25 23:59:59'
group by
    merchant_id, order_status_id
having
    order_status_id = 10

union

select
    merchant_id, count(order_status_id)
from
    OrderDetails
where
    OrderDetails.delivery_date between '2019-07-24 00:00:00' and '2019-11-25 23:59:59'
group by
    merchant_id, order_status_id
having
    order_status_id = 11;

但它会在两列中返回所有结果，我希望它在 4 中有，例如 id 、count、return、已发送请提出任何建议

Answer 1

你需要sum()和count()，你可以忽略你的union。

select merchant_id
    , count(1)
    , sum(case when order_status_id = 10 then 1 else 0 end) as returned
    , sum(case when order_status_id = 11 then 1 else 0 end) as delivered
from  OrderDetails 
where delivery_date between '2019-07-24 00:00:00' and '2019-11-25 23:59:59' 
group by merchant_id