我应该如何消除ACCESS中SQL查询中的NULL值元组

Question

我目前正在ACCESS中编写查询。但是，结果具有NULL值的行。以下是我的代码：

SELECT 
DISTINCT A.pcode AS [Product Type], 
Sum([footage]*[lb_ft]*12) AS TotalWeightUsed, 
Sum(A.totlength) AS TotalLength, 
Count(A.pcode) AS NumberOfPieces, 
A.date_

FROM A

GROUP BY A.pcode, A.date_
HAVING  (((A.date_)=#4/16/2014#)) and A.pcode IS NOT NULL;

有一行值为NULL的A.pcode。我尝试过“Distinct”和“A.pcode IS NOT NULL”，但它们无法消除NULL值行。我是Access的新手。我想知道我能做些什么。

Answer 1

我猜这应该有效。您不应该需要 DISTINCT 限定符：

SELECT 
  A.pcode AS [Product Type], 
  Sum([footage]*[lb_ft]*12) AS TotalWeightUsed, 
  Sum(A.totlength) AS TotalLength, 
  Count(A.pcode) AS NumberOfPieces, 
  A.date_
FROM A
WHERE 
  A.date_ = #4/16/2014# 
  AND A.pcode IS NOT NULL
GROUP BY 
  A.pcode, 
  A.date_;