今天是客户的第一个订单周年纪念日吗？

Question

我正在尝试使用 MySQL 查询来查看今天是否是客户的第一个订单日期。我正在查看单个数据库 table - tblOrders

到目前为止，我的尝试导致退回的订单恰好落在今天的某个时间，但不是他们的 'first' 订单。

SELECT FirstName, LastName, Email, COUNT(OrderID) AS NumberOfOrders, CreateDate
FROM tblOrders
WHERE (MONTH(CreateDate) = MONTH(NOW()) 
    AND DAY(CreateDate) = DAY(NOW()))
GROUP BY Email
ORDER BY CreateDate

我觉得我需要一个子查询，但我正在转动轮子。

Answer 1

如果你想要客户的第一个订单，你需要使用 MIN(CreateDate)，但是聚合不能出现在 WHERE 它们必须出现在 HAVING，所以你的查询将是：

SELECT  o.FirstName, 
        o.LastName, 
        o.Email, 
        COUNT(o.OrderID) AS NumberOfOrders, 
        MIN(o.CreateDate) AS FirstOrder
FROM    tblOrders AS o
GROUP BY o.FirstName, o.LastName, o.Email
HAVING  MONTH(MIN(o.CreateDate)) = MONTH(NOW()) 
AND     DAY(MIN(o.CreateDate)) = DAY(NOW());

你的问题是你的计数将只计算与今天相同 month/day 的订单，而不是该客户的所有订单，所以如果你只想知道客户详细信息很好，但是如果您需要该客户的订单总数，您将需要一个子查询（如您所想）：

SELECT o.FirstName, o.LastName, o.Email, o.NumberOfOrders, o.FirstOrder
FROM  ( 
        SELECT o.FirstName, 
               o.LastName, 
               o.Email,
               MIN(o.CreateDate) AS FirstOrder,
               COUNT(*) AS NumberOfOrders
        FROM   tblOrders AS o
        GROUP BY o.FirstName, o.LastName, o.Email
      ) AS o
WHERE MONTH(o.FirstOrder) = MONTH(NOW())
AND   DAY(o.FirstOrder) = DAY(NOW());

Answer 2

WITH cte AS (
    SELECT *, MIN(CreateDate) OVER (PARTITION BY Email) CreateDate 
    FROM tblOrders
)
SELECT FirstName, LastName, Email, COUNT(DISTINCT OrderID) AS NumberOfOrders, CreateDate 
FROM cte
WHERE DATE_FORMAT(CreateDate, '%m%d') = DATE_FORMAT(CURRENT_DATE, '%m%d')
GROUP BY FirstName, LastName, Email, CreateDate

今天是客户的第一个订单周年纪念日吗？

Is Today the Customer's First Order Anniversary?

mysql

sql