[英]How do I do this sql select query?
我有下表:
+----+-----------+-----+
| p1 | p2 | model| res |
+----+-----------+-----+
| 1 | a | dog | 1 |
| 2 | a | dog | 2 |
| 1 | b | dog | 3 |
| 2 | b | dog | 4 |
| 1 | a | cat | 10 |
| 2 | a | cat | 2 |
| 1 | b | cat | 10 |
| 2 | b | cat | 1 |
+----+-----------+-----+
我想要的是,對於p1和p2的每個組合,選擇獲得所有模型的最低總和的一個)。 在這種情況下的總分是:
p1=1, p2=a: 1+10=11
p1=2, p2=a: 2+2=4
p1=1, p2=b: 3+10=13
p1=2, p2=b: 4+1=5
所以我想得到下表:
+----+-----------+-----+
| p1 | p2 | model| res |
+----+-----------+-----+
| 2 | a | dog | 2 |
| 2 | a | cat | 2 |
+----+-----------+-----+
注意:可能有更多p列(即p3,p4,...)
我應該使用什么sql select查詢來獲得上面所需的表?
http://sqlfiddle.com/#!7/af26b/5
SELECT t1.*
FROM TEST t1
JOIN (
SELECT p1, p2
FROM TEST
GROUP BY p1, p2
ORDER BY SUM(res)
LIMIT 1) t2 ON t1.p1 = t2.p1 AND t1.p2 = t2.p2
這樣的事情有幫助嗎?
select * from the_table
group by model # do it for each distinct model
order by res ascending # to get the lower ones first so that limit can pick them
limit 1 # for each group, i think it will do that.
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