Question

两张桌子

客户
订单

如果在日期1和日期2之间找到所有客户的订单，即使他们有0个订单？

这是我到目前为止所做的工作：

select c.customer_name
     , c.date_created
     , o.grandtotal
     , o.order_date
  from Customers c
  left 
  join Orders o 
    on c.customer_id = o.customer_id
 where exists (select o1.* from Orders o1) 
   and c.customer_id in (1, 2, 3, 4)
 group 
    by c.customer_name

我需要按日期订购：

select c.customer_name, c.date_created, o.grandtotal, o.order_date
from Customers c
left join Orders o on c.customer_id = o.customer_id
where exists (select o1.* from Orders o1) 
and o.order_date between '2018-01-01' and '2018-01-18'
and c.customer_id in (1, 2, 3, 4)
group by c.customer_name

Answer 1

这应该这样做。如果您想查看所有特定客户及其订单。

t = [ [ 0,0,0]
      [ 0,0,0]
      [ 0,0,0] ]

c = [ 0, 1, 2 ]

v = [ 1, 10, 1000 ]

i = 1

# then f(t,c,v,i) where f is the broadcast function
f(t,c,v,i) outputs:

t = [ [ 10,  0,  0 ]
      [  0, 10,  0 ]
      [  0,  0, 10 ] ]

Answer 2

根据您提供的超级有限信息，我很确定您正在尝试进行LEFT JOIN。看看http://www.dofactory.com/sql/left-outer-join，看一个听起来与你所描述的很相似的例子。

Mysql查询查找两个日期之间有0个订单的客户

2 个答案: