Question

我有一个类似的查询：

SELECT *
FROM table
GROUP BY sid
ORDER BY datestart desc
LIMIT 10

返回最后10个sid组。

对于这些组中的每一组，我需要具有最低日期开始值

的行的标题列

我尝试使用

SELECT *, min(datestart)

但是没有返回具有最小datestart值的行，只返回最低的datestart。我需要从最低日期开始的标题。

（相关）表格结构：

    CREATE TABLE `table` (
  `title` varchar(1000) NOT NULL,
  `datestart` timestamp NOT NULL default CURRENT_TIMESTAMP,
  `sid` bigint(12) unsigned NOT NULL,
  KEY `datestart` (`datestart`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

有什么想法吗？

Answer 1

尝试此查询。您将获得预期的结果。如果不起作用，则按Table_2.datestart > Table_1.datestart

更改Table_2.datestart < Table_1.datestart

SELECT title, datestart
FROM `table` AS Table_1
LEFT JOIN `table` AS Table_2 ON (Table_2.sid = Table_1.sid AND Table_2.datestart > Table_1.datestart)
Table_2.sid IS NULL;

已编辑的查询

SELECT Table_1.title, Table_1.datestart
FROM `table` AS Table_1
LEFT JOIN `table` AS Table_2 ON (Table_2.sid = Table_1.sid AND Table_2.datestart > Table_1.datestart)
Table_2.sid IS NULL;

Answer 2

更新回答

select t1.* from `table` as t1
inner join (
select sid,min(datestart) as elder
from `table`
group by sid
order by elder desc limit 10) as t2
on t1.sid = t2.sid and t1.datestart = t2.elder

在（sid，datestart）上使用复合索引

MySQL Group通过获取具有最小日期值的标题列

2 个答案: