Question

我使用MySQL数据库管理组织的捐款。捐赠者可以捐赠多份捐款。因此，我有两个表：donators包含有关捐赠者的信息，donations包含有关捐赠时间和金额的信息。两个表都通过donatorID连接。

我想读出有关每个不同捐赠者的信息。该清单应按上次捐赠日期排序。我想出了下面的代码，但是它使用了第一次捐赠的日期而不是最后一次捐赠。

如何为每位捐赠者使用最新的捐赠日期？

SELECT
    DISTINCT(`donators`.`name`),
    `donators`.`city`,
    `donators`.`country`,
    `donators`.`website`
FROM
    `donators`
INNER JOIN
    `donations`
ON
    `donators`.`donatorID` = `donations`.`donatorID`
ORDER BY `donations`.`date` DESC

Answer 1

SELECT  a.*, b.max_DATE
FROM    Donators a
        INNER JOIN
        (
            SELECT  DonatorID, MAX(date) max_DATE
            FROM    Donations
            GROUP   BY DonatorID
        ) b ON a.DonatorID = b.DonatorID
ORDER   BY  b.max_DATE DESC

如果您想根据最新的捐赠日期显示donation表的记录，

SELECT  a.*, c.*
FROM    Donators a
        INNER JOIN Donations c
            ON a.DonatorID = c.DonatorID
        INNER JOIN
        (
            SELECT  DonatorID, MAX(date) max_DATE
            FROM    Donations
            GROUP   BY DonatorID
        ) b ON  c.DonatorID = b.DonatorID AND
                c.date = b.max_DATE
ORDER   BY c.date DESC

Answer 2

假设您对donations表中的各个值不感兴趣，可以使用此查询：

SELECT
    `donators`.`name`,
    `donators`.`city`,
    `donators`.`country`,
    `donators`.`website`,
    MAX(`donations`.`date`) AS LastDate
FROM `donators`
INNER JOIN `donations` ON `donators`.`donatorID` = `donations`.`donatorID`
GROUP BY 
    `donators`.`name`,
    `donators`.`city`,
    `donators`.`country`,
    `donators`.`website`
ORDER BY
    LastDate DESC

Answer 3

SELECT
    who.name
    , who.city
    , who.country
    , who.website
    , what.thedate
FROM donators who
JOIN donations what ON what.donatorID = who.donatorID
WHERE NOT EXISTS (
        SELECT * 
        FROM donations nx  
        WHERE nx.donatorID = what.donatorID
        AND nx.thedate > what.thedate
        )
ORDER BY what.thedate DESC
        ;

只选择不同的名称＆＃39;并按照他们的最新日期排序他们。

3 个答案: