Question

我在Access 2013数据库中有一个查询，它会计算符合特定条件的记录数量。但是，有些情况下没有记录匹配，查询也不返回任何内容。这会导致问题，因为我在计算中使用此值。请从下面的查询中找到SQL代码。

SELECT [Main Database].Renewal,
[Main Database].[2014/15 - Permission to Review],
Count(Main Database].[2014/15 - Permission to Review]) AS [CountOf2014/15 - Permission to Review]
FROM [Main Database]
GROUP BY [Main Database].Renewal, [Main Database].[2014/15 - Permission to Review]
HAVING ((([Main Database].Renewal) Like "**/05/****") AND (([Main Database].[2014/15 - Permission to Review])="Yes"));

我尝试过使用Nz函数和IIF（IsNull（[]）），但这些都不起作用。

我做错了什么或找到我想要的替代方法吗？

编辑 - 带子查询的新代码

SELECT COUNT (*) AS iniSumNov
FROM (
SELECT [Main Database].Renewal, [Main Database].[2014/15 - Initial Contact], 
Count([Main Database].[2014/15 - Initial Contact])
AS [CountOf2014/15 - Initial Contact]
FROM [Main Database]
GROUP BY [Main Database].Renewal, [Main Database].[2014/15 - Initial Contact]
HAVING ((([Main Database].Renewal) Like "**/11/****") AND (([Main Database].[2014/15 - Initial Contact])="Yes"))
);

Answer 1

使用此.. ..

 SELECT A.Renewal as Renewal ,
 A.[2014/15 - Permission to Review] as Permission_to_Review,
 IIF(isNull(Count(A.[2014/15 - Permission to Review])),0,Count(A.[2014/15 - Permission to Review])) AS count_Permission_to_Review 
 FROM [Main Database] A
 where (((A.Renewal) Like "**/05/****") AND ((A.[2014/15 - Permission to Review])="Yes")) 
 GROUP BY A.Renewal, A.[2014/15 - Permission to Review] 
;

Answer 2

在子查询上使用COUNT（*）：

SELECT COUNT(*) as NbRecords
FROM (
    SELECT ...whatever you need
     )

如果子查询为空，则主查询将返回NbRecords = 0

如果Access 2013中没有匹配的记录，如何使查询返回0？

2 个答案: