Question

基本上我有这张表：

表 QID，UID，系统，添加（unix时间戳），错误

我尝试做的是通过UID选择一行，但在此之前，该表通过添加＆＃39;所以它的时间戳为DESC顺序，然后得到单行及其在排序表中的位置。

我目前有这个排序行，但我如何从中获取单行：

SET @rank=0;
SELECT @rank := @rank +1 AS rank, UID
FROM table
GROUP BY UID
ORDER BY added DESC

Answer 1

您将使用子查询：

SELECT *
FROM (SELECT @rank := @rank +1 AS rank, UID, added
      FROM (SELECT UID, added
            FROM t cross join
                   (SELECT @rank := 0) var
            GROUP BY UID
            ORDER BY added ASC
           ) t
     ) t
WHERE UID = 12346;

一个问题是，当给定added有多行时，UID是不确定的。我怀疑你想要MAX(added)。

Answer 2

您可以按照以下方式执行以下操作：

SELECT COUNT(*)+1 AS rank FROM table
WHERE added < (SELECT added FROM table WHERE UID=123)

或许这个：

SELECT * FROM (
    SELECT @rank := @rank+1 AS rank, UID
    FROM table
    GROUP BY UID
    ORDER BY added ASC
) tmp WHERE UID=123

SQL（mysql）排序表并获取其在排序表中的位置的行？

2 个答案: