如何在MySQL中使用WHERE和MAX获取最新数据

Question

This is my current MySQL Table:

Crop             ID  Price  DateUpdated             Area
Okra             4   50     2014-02-05 21:42:26     Bulua
Eggplant         5   20     2014-02-05 21:42:26     Lapasan
Okra             6   35     2014-02-05 21:42:26     Agora
Cauliflower      8   300    2014-02-05 21:42:26     Patag
Onion            9   10     2014-02-05 22:02:34     Cogon
Kalabasa         10  50     2014-02-05 22:59:30     Cogon
Garlic           11  130    2014-02-05 22:59:44     Cogon
Onion            14  34.4   2014-02-05 23:12:21     Cogon
Onion            15  54     2014-02-07 02:40:13     Cogon

I want to query all 'Crops' with their 'Price' as latest in the area name 'Cogon' . This is the last query that I used:

SELECT ID, Crop, Area, MAX( DateUpdated ) 
AS Latest, DateUpdated, Price 
FROM crops 
WHERE Area = TRIM( 'Cogon' ) 
GROUP BY Area, Crop;

In which I want to get all crops in 'Cogon' with their latest prices.

Well the syntax above outputs all the crops in 'Cogon'. However, it does not output the latest Price of Onion (ID 14) but instead outputs the older data (ID 9).

Answer 1

What if you say like

SELECT Crop, 
Area, 
DateUpdated, 
Price 
FROM crops cr
WHERE trim(Area) = 'Cogon' 
and
DateUpdated = (select max(DateUpdated) 
               from crops 
               where Crop = cr.Crop and trim(Area) = 'Cogon' ) ;

Answer 2

您想按日期更新ORDER BY DateUpdated DESC或按ORDER BY ID DESC