Question

我试图显示一个“空”＆＃39;使用＆＃39; IFNULL＆＃39;将值设为0但它返回所有行为null或0.一切正常，直到我添加＆＃39; lounge2＆＃39;桌子和＆＃39; lounge2order2＆＃39;表。 order2.lounge2orderid是＆＃39; NULL＆＃39;。我知道这与“加入”有关。但不确定在哪里或哪个地方实施。

谢谢大家......

SELECT orders2.orderid, orders2.orderdate, branch2.branchname, COUNT(orders2.garment2orderid) AS 'no gar orders', SUM(garment2.hireprice) as 'total gar sold',
COUNT(orders2.lounge2orderid+IFNULL(orders2.lounge2orderid,0)) as 'No of lounge sales', SUM(lounge2.hirerate)

from orders2, branch2, garment2, garment2order2, lounge2, lounge2order2

WHERE orders2.orderid IN

            (SELECT orders2.orderid FROM orders2 
                WHERE orders2.branchid = 2 
                AND YEAR(orders2.orderdate)= 2011) 

AND branch2.branchid IN

            (SELECT branch2.branchid from branch2
                  WHERE branch2.branchid = orders2.branchid)

AND garment2order2.garment2orderid IN
            (SELECT garment2order2.garment2orderid FROM garment2order2
                WHERE garment2order2.garment2orderid = orders2.garment2orderid)

AND garment2.garmentid IN

            (SELECT garment2.garmentid FROM garment2
                WHERE garment2.garmentid = garment2order2.garmentid)

AND lounge2order2.lounge2orderid IN
            (SELECT lounge2order2.lounge2orderid FROM lounge2order2
                WHERE lounge2order2.lounge2orderid = orders2.lounge2orderid)

AND lounge2.loungeid IN

            (SELECT lounge2.loungeid FROM lounge2
                WHERE lounge2.loungeid = lounge2order2.loungeid)

Answer 1

首先，尽量避免FROM orders2, branch2, garment2, garment2order2, lounge2, lounge2order2它必须是JOIN ... ON语句。这将有助于您调试，让我们了解您的逻辑和表关系。

要使SUM或COUNT等任何agregate函数正常工作，您应该设置GROUP BY语句。

因为我不知道您的数据库结构是什么样的。

这是我的尝试：

SELECT 
  orders2.orderid, 
  orders2.orderdate, 
  COUNT(orders2.garment2orderid) AS 'no gar orders', 
  branch2.branchname, 
  SUM(garment2.hireprice) as 'total gar sold',
  SUM(IF(orders2.lounge2orderid IS NULL,1,0)) as 'No of lounge sales', 
  SUM(lounge2.hirerate)
FROM orders2
LEFT JOIN branch2
ON branch2.branchid = orders2.branchid
LEFT JOIN garment2order2
ON  garment2order2.garment2orderid = orders2.garment2orderid
LEFT JOIN garment2
ON garment2.garmentid = garment2order2.garmentid
LEFT JOIN lounge2order2
ON lounge2order2.lounge2orderid = orders2.lounge2orderid
LEFT JOIN lounge2
ON lounge2.loungeid = lounge2order2.loungeid)    
WHERE orders2.branchid = 2 
  AND YEAR(orders2.orderdate)= 2011
GROUP BY orders2.orderid

MYSQL数据库是IFNULL查询

1 个答案: