I have a query like:
SELECT *
FROM table
GROUP BY sid
ORDER BY datestart desc
LIMIT 10
which returns the last 10 sid groups.
For each of these groups, I need the title column of the row with the lowest datestart value
I tried using
SELECT *, min(datestart)
but that didn't return the row with the smallest datestart value, just the lowest datestart. I need the title from the lowest datestart.
(Relevant) Table Structure:
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 DEFAUL开发者_运维问答T CHARSET=utf8;
Any ideas?
Updated answer
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
Use a composite index on (sid,datestart)
Try this query. You will get expected results. If it don't work change Table_2.datestart > Table_1.datestart
by 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;
Edited query
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;
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