我有这个 MySQL 表名为records。以下是其内容。

id  record_id   Data1   Data2   Time 
1   1           null    1       1/1/16
2   1           1       null    1/3/16
3   1           2       null    1/4/16
4   1           null    3       1/5/16
5   2           1       null    2/1/16
6   2           1       null    2/3/16
7   2           7       null    2/4/16
8   2           null    5       2/5/16

我想要一个 MySQL 查询来检索每个列的最后一个非空记录record_id。结果看起来像这样；

record_id   Data1   Data2   Time 
1           2       3       1/5/16
2           7       5       2/5/16

这个问题的棘手部分是涉及多个列。

SELECT t1.*
FROM yourTable t1
INNER JOIN
(
    SELECT record_id, MAX(Time) AS Time
    FROM yourTable
    GROUP BY record_id
) t2
    ON t1.record_id = t2.record_id AND
       t1.Time = t2.Time

如果您只是想要greatest数据和时间列的值，然后查看@Matt 给出的答案。但你的语言让人不清楚你真正想要什么。

Update:

像这样的东西可能会给出你想要的结果：

SELECT a.record_id,
       a.Data1,
       b.Data2,
       c.Time
FROM
(
    SELECT t1.record_id,
           t1.Data1
    FROM yourTable t1
    INNER JOIN
    (
        SELECT record_id,
               MAX(CASE WHEN Data1 IS NULL THEN 0 ELSE id END) AS Data1Id
        FROM yourTable
        GROUP BY record_id
    ) t2
        ON t1.record_id = t2.record_id AND
           t1.Id = t2.Data1Id
) a
INNER JOIN
(
    SELECT t1.record_id,
           t1.Data2
    FROM yourTable t1
    INNER JOIN
    (
        SELECT record_id,
               MAX(CASE WHEN Data2 IS NULL THEN 0 ELSE id END) AS Data2Id
        FROM yourTable
        GROUP BY record_id
    ) t2
        ON t1.record_id = t2.record_id AND
           t1.Id = t2.Data2Id
) b
    ON a.record_id = b.record_id
INNER JOIN
(
    SELECT t1.record_id,
           t1.Time
    FROM yourTable t1
    INNER JOIN
    (
        SELECT record_id,
               MAX(CASE WHEN Data2 IS NULL THEN 0 ELSE id END) AS TimeId
        FROM yourTable
        GROUP BY record_id
    ) t2
        ON t1.record_id = t2.record_id AND
           t1.Id = t2.TimeId
) c
    ON a.record_id = c.record_id

演示在这里：

SQLFiddle