Question

考虑以下MySQL表：

MORTALITY （包含哪些饲养者已经死亡的仔猪）

raiserID  |  issuedDate  |  rotationNo |  numberDead
-----------------------------------------------------
   0052      2012-08-03         1             3

PIGLET_PO （包含由饲养者购买仔猪交易）

〜提升者可以在此处拥有多条记录

raiserID  |  deliveredDate  |  rotationNo  |  noOfDeliveredPigs  |  sellerID
------------------------------------------------------------------------------
   0052       2012-07-20          1                  10                1
   0052       2012-07-21          1                  15                1

SELLER_LIST

sellerID |  sellerName  
------------------------
    1       Solar Farm

预期结果：

sellerName  |  population  |  deceased
-----------------------------------------
Solar Farm         25            3

Raiser是一个照顾/养猪/生猪的人
rotationNo是一个唯一标识符，指的是提升者已经或正在进行的提升周期

到目前为止，我有以下查询给出了类似于预期结果的结果，唯一的问题是我得到的值为6而不是已故列的3 。我不确定，但我的猜测是它与有两个记录/行的piglet_po有关。我在这里错过了什么？

SELECT s.sellerName AS sellerName, SUM(p.noOfDeliveredPigs) AS population, SUM(numberDead) AS heads
FROM mortality m

JOIN piglet_po p
ON m.raiserid = p.raiserid
AND m.rotationNo = p.rotationNo

JOIN seller_list s
ON p.sellerID = s.sellerID

// This WHERE condition and the given string value that follow came from and is based on
a select drop-down box and shouldnt be modified since this is how I display them in html
WHERE DATE_FORMAT(m.issuedDate, '%M %Y') = 'August 2012' 
GROUP BY sellerName
HAVING SUM(numberDead) != 0

Answer 1

这是因为您在表piglet_po(p.rotationNo)的连接中使用的列具有重复值。而是尝试这个，或者你也可以在DISTINCT语句中使用SELECT子句。

SELECT s.sellerName AS sellerName, SUM(p.noOfDeliveredPigs) AS population, 
       SUM(numberDead) AS heads
FROM mortality m
    JOIN (SELECT rotationNo, raiserid, sellerID, SUM(noOfDeliveredPigs) AS noOfDeliveredPigs
          FROM  piglet_po 
          GROUP BY rotationNo, raiserid, sellerID
         ) p
         ON m.raiserid = p.raiserid
            AND m.rotationNo = p.rotationNo
    JOIN seller_list s
         ON p.sellerID = s.sellerID
WHERE DATE_FORMAT(m.issuedDate, '%M %Y') = 'August 2012'
GROUP BY sellerName
HAVING SUM(numberDead) != 0;

Answer 2

试试这个：

select sellername , population  , deceased 
from
    (select p.rotationno,p.raiserid,s.sellername as sellername
           , sum(p.noofdeliveredpigs) as population 
    from piglet_po p
    join seller_list s
    on p.sellerid = s.sellerid 
    group by p.rotationno,p.raiserid,sellername)p
join
    (select rotationno,raiserid,sum(numberdead) as deceased
    from mortality 
    where date_format(issueddate, '%m %y') = 'august 2012'
    group by rotationno,raiserid)m
on m.raiserid = p.raiserid
and m.rotationno = p.rotationno

MySQL加入重复问题？

2 个答案: