MySQL查询与分组 [英] MySQL Query with Group By

问题描述

我玩过很多不同的查询，但一直没能找到这个项目的正确语法。我真的希望有人能理解我的混乱。

I have played around with many different queries, but haven't been able to locate the right syntax for this project.. I really hope someone can make sense of my mess.

我有一张包含订单的表，每个订单一行，每行包含客户编号，采购订单编号和订单日期等信息。采购订单号码可以绑定到一个或多个订单，这是我迷路的地方。我试图创建一个包含客户编号，PO＃，最早订单日期和最后一个订单日期（根据PO＃分组）的单个行的查询。

I have a table with orders, one row per order, and each row containing info such as the customer number, PO#, and date of the order. A PO number can be tied to one or more orders, which is where I am getting lost. I am trying to create a query that will produce a single row containing the customer number, PO#, date of the earliest order, and date of the last order, grouped by the PO#.

任何指向正确方向的指针都会非常感谢！

Any pointers in the right direction will by much appreciated!

推荐答案

这将得到订单和范围的东西......

This will get the order and range stuff...

select
      o.PONumber,
      o.CustomerID,
      count(*) as TotalOrders,
      min( o.OrderID ) as FirstOrder,
      min( o.OrderDate) as FirstOrderDate,
      max( o.OrderID ) as LastOrder,
      max( o.OrderDate) as LastOrderDate
   from
      Orders o
   group by
      o.PONumber,
      o.CustomerID

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