Question

说我有下表：

CREATE TABLE `table` (
    id INT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
    userid INT UNSIGNED NOT NULL,
    reference INT,
    `datetime` DATETIME
) Engine=InnoDB;

我想从表中选择，按引用分组并按DATE排序，还要按最新参考条目排序？

例如：

reference: 79
datetime: 2011-12-31 00:32:30

reference: 77
datetime: 2011-12-31 00:40:30

reference: 77
datetime: 2011-12-31 00:43:30

reference: 77
datetime: 2011-12-31 00:45:30

reference: 78
datetime: 2011-12-31 00:47:30

他们应该按照这个顺序显示：78,77（00:45 one），79

我目前将此作为我的查询：

SELECT * 
  FROM `table` 
  WHERE `userid` = '" . mysql_real_escape_string($id) . "' 
  GROUP BY `reference` 
  ORDER BY `datetime` DESC

如何让此查询生效？因此，当已经存在的引用获得另一个条目时，它会跳转到列表的顶部吗？

谢谢

Answer 1

尝试

SELECT id, userid, reference, MAX(datetime) AS datetime
FROM `table` WHERE `userid` = ID 
GROUP BY `reference` 
ORDER BY `datetime` DESC

Answer 2

您需要指定分组依据子句附近的所有列。

SELECT id, userid, reference, MAX(datetime) AS datetime
FROM `table` WHERE `userid` = ID 
GROUP BY `id`, `userid`, `reference`
ORDER BY `datetime` DESC

mySQL查询，分组依次按最新分组排序？

2 个答案: