我有一個複雜查詢的問題,我不知道如何編寫它。 我有下表:獲取按最近時間過濾的行mysql
+---------------+-----------+----------+--------------------------+
|id_incidencia | id_alarma | idaction | concat(fecha, ' ', hora) |
+---------------+-----------+----------+--------------------------+
| 18488 | 551 | 1 | 2016-08-29 14:55:47 |
| 18491 | 551 | 7 | 2016-08-29 15:02:47 |
| 18493 | 551 | 6 | 2016-08-29 15:37:39 |
| 18495 | 551 | 7 | 2016-08-29 15:41:27 |
| 19263 | 551 | 6 | 2016-09-16 15:17:27 |
| 19429 | 5151 | 5 | 2016-09-19 09:01:17 |
| 19447 | 5151 | 5 | 2016-09-19 09:25:23 |
| 19500 | 5151 | 5 | 2016-09-20 09:38:11 |
| 19532 | 5151 | 5 | 2016-09-23 15:02:50 |
| 19526 | 5151 | 6 | 2016-09-23 11:23:27 |
| 19528 | 5151 | 6 | 2016-09-23 11:28:01 |
| 19527 | 5151 | 7 | 2016-09-23 11:25:18 |
| 19529 | 5151 | 7 | 2016-09-23 11:28:08 |
+---------------+-----------+----------+--------------------------+
我想有從查詢下一個結果:
idaction | id_alarma | datetime
---------+-----------+---------
7 | 551 | 2016-08-29 15:41:27
7 | 5151 | 2016-09-23 11:28:08
這意味着,我要爲每個組id_alarma
的價值,我想最近一次的最後一行,它的值爲idaction
。問題是,當我執行下一個查詢時,idaction
中的值與日期時間字段不匹配。
,我提到的查詢是:
SELECT a.id,
nia.idaction,
MAX(CONCAT(nia.fecha, ' ', nia.hora))
FROM nectar_incidencias_alarma nia
INNER JOIN alarmas a
ON a.id=nia.id_alarma
WHERE nia.idaction IN (6,7)
GROUP BY a.id
我提的就是查詢:SELECT a.id,nia.idaction,MAX (CONCAT(nia.fecha,'',nia.hora))FROM nectar_incidencias_alarma nia INNER JOIN報警a ON a.id = nia.id_alarma WHERE nia.idaction IN(6,7)GROUP BY a.id – mp3man
但是551 | 6比551 | 7更新!!!?! – Strawberry