问题
Ref : GROUP BY WITH HAVING ( DISTINCT ) : PHP , MYSQL
I got answer (thanks @coytech) but I need one more column in it:
as per:
id | mid | pid | owgh | nwgh |
1 3 12 1.5 0.6
2 3 12 1.5 0.3
3 3 14 0.6 0.4
4 3 15 1.2 1.1
5 4 16 1.5 1.0
6 4 17 2.4 1.2
7 3 19 3.0 1.4
I got answer
Select mid , COUNT(distinct pid) as cpid , SUM(nwgh) as totalnwgh from test GROUP BY mid
sqlfiddle : http://sqlfiddle.com/#!9/45e68/2
mid cpid totalnwgh
3 4 3.8
4 2 2.2
But above I need one more column that's as below : totowgh
mid cpid totalnwgh totowgh
3 4 3.8 6.3 (DISTINCT value as per pid column)
4 2 2.2 3.9
where totowgh = 6.3 come by DISTINCT value as per pid column
That's mid = 3 has count 5 but distinct pid = 4 for mid=3 same way "distinct" owgh = 6.3 for mid=3 and distinct pid.
As pid=12 is count 1 time hence,
1.5 + 0.6 + 1.2 + 3 = 6.3 ( please not this is as per DISTINCT value of pid )
Please note : i need owgh value as per distinct pid or group by pid .. because if i replace value of owgh 0.6 with 1.5 then it will be 5.7 instead of 7.2 but value of owgh 0.6 belong to pid = 14 and not pid = 12 hence totalcount of owgh change ...but i need is 7.2
SEE WHAT I MEANS : sqlfiddle.com/#!9/2a53c/6
回答1:
OK, per your followup comment this is what I came up with. First get the grouping of the distinct owgh and then perform a JOIN with main query. See a demo fiddle http://sqlfiddle.com/#!9/a56e4/1
SELECT t.`mid` ,
COUNT(distinct t.`pid`) AS countmid ,
SUM(t.`nwgh`) AS totalnwgh,
xx.`totowgh`
FROM test t JOIN (
select mid, sum(owgh) as totowgh
from (
select distinct mid, owgh from test) x
group by mid) xx ON t.`mid` = xx.`mid`
GROUP BY t.`mid`;
It will result in
mid countmid totalnwgh totowgh
3 4 3.8 6.3
4 2 2.2 3.9
来源：https://stackoverflow.com/questions/32536393/2-group-by-with-distinct-sum-count-php-mysql