我有这样的表格:
v | day | month | year
1 1 1 1950
2 2 1 1950
3 3 1 1950
1 1 2 1950
1 1 2 1951
2 1 2 1952
我已使用此查询来选择 MIN
SELECT SUM(v) AS sum_val, year, month
FROM `d`
GROUP BY year, month
这将导致
sum_val | year | month
6 1950 1
1 1950 2
1 1951 2
2 1952 2
如何选择指定年份按月分组的 sum_val 的最大值? 我已经尝试过了
SELECT (MAX(f.sum_val)) AS max_sum, f.year, f.month
FROM (
SELECT SUM(v) AS sum_val, year, month
FROM `d`
GROUP BY year, month
) AS f
GROUP BY month
但这错误地将年份分配给值
max_sum | year | month
6 1950 1
2 1950 2 <--- should be 1952
SqlFiddle:http://sqlfiddle.com/#!9/ab23b4/6/0
最佳答案
您可以在连接中使用一些基于 sum_val 的子查询
select t2.sum_val, t2.year, t2.month
from (
SELECT SUM(v) AS sum_val, year, month
FROM `d`
GROUP BY year, month
) t2
INNER JOIN (
select max(sum_val) max_val, year
from (
SELECT SUM(v) AS sum_val, year, month
FROM `d`
GROUP BY year, month
) t
group by year
) t3 on t3.max_val = t2.sum_val and t3.year = t2.year
注意,如果有两行与 max val 匹配,查询将返回两行
关于MySQL - 选择一年中总和的最大值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/54731584/