mysql - 如何为每个“订单号”检索具有最大“交货日期”的记录

Question

我正在寻找按表的订单号检索所有记录和列，TEST其中每个订单号MAX的列orderDeliveryDate等于昨天。以下代码不起作用：

SELECT  T.* 
FROM    TEST T
    INNER JOIN(
            SELECT orderNum, MAX(orderDeliveryDate) AS maxDeliveryDate
            FROM TEST
            GROUP BY orderNum) MX
        ON T.orderNum= MX.orderNum
        AND T.orderDeliveryDate = MX.maxDeliveryDate
        AND MX.maxDeliveryDate = DATE_SUB(curdate(),INTERVAL 1 DAY)

Answer 1

在比较之前将列转换为日期，为了提高效率，将测试移动到子查询中：

SELECT  T.* 
FROM TEST T
JOIN(
    SELECT orderNum, DATE(MAX(orderDeliveryDate)) AS maxDeliveryDate
    FROM TEST
    GROUP BY orderNum
    HAVING DATE(MAX(orderDeliveryDate)) = DATE_SUB(curdate(),INTERVAL 1 DAY)
    ) MX
    ON T.orderNum= MX.orderNum
    AND DATE(T.orderDeliveryDate) = MX.maxDeliveryDate

Answer 2

这应该这样做：

SELECT * FROM TEST 
WHERE ORDERNUM IN 
    (SELECT ORDERNUM, MAX(orderDeliveryDate)
     FROM TEST GROUP BY ORDERNUM 
     HAVING DATE(MAX(orderDeliveryDate)) = DATE(DATE_SUB(curdate(),INTERVAL 1 DAY)))

我的猜测是 orderDeliveryDate 是 DateTime，因此将其转换为 Date 将解决您的问题。您的原始查询可以转换为日期，我认为我的查询更简单一些。