2

我将从发布我的查询开始...

SELECT [copyright status], 
sum(IIF(layer='key info',1,0)) AS [Key Info],
sum(IIF(layer='approaches',1,0)) AS [Approaches],
sum(IIF(layer='research',1,0)) AS [Research]
FROM resources
GROUP BY [copyright status]

UNION

SELECT [lw status],
sum(IIF(layer='key info',1,0)) AS [Key Info],
sum(IIF(layer='approaches',1,0)) AS [Approaches],
sum(IIF(layer='research',1,0)) AS [Research]
FROM resources
WHERE [lw status] = 'In Reserve'
GROUP BY [lw status]

UNION 

SELECT [lw status],
sum(IIF(layer='key info',1,0)) AS [Key Info],
sum(IIF(layer='approaches',1,0)) AS [Approaches],
sum(IIF(layer='research',1,0)) AS [Research]
FROM resources
WHERE [lw status] = 'Published'
GROUP BY [lw status];

（希望这很容易阅读）

它按我的意图工作，但是我想在查询中再添加一个函数。

在第一个SELECT查询之后，我想添加一个额外的查询，该查询总计三个总和（关键信息、方法、研究）中的每一个。我尝试添加的语法如下：

<Previous Query>
UNION
SELECT, 
sum(IIF(layer='key info',1,0)) AS [Key Info],
sum(IIF(layer='approaches',1,0)) AS [Approaches],
sum(IIF(layer='research',1,0)) AS [Research]
FROM resources
UNION 
<Next Query>

但是，当我尝试运行它时，我收到一条错误消息，显示“联合查询的两个选定查询表中的列数不匹配”。

我不确定我是否对此过于雄心勃勃。

此外，是否有更有效的方式来格式化初始查询？

如果有什么不同，layer、copyright status 和 lw status 中的值分别存储在单独的表中，并通过表格设计模式中的组合框绘制到资源表中。我正在使用 Access 2003。

如果需要更多信息，请告诉我。

谢谢。

4

3 回答 3

2

的所有部分的列数必须相等union。您可以null为摘要行添加第一列：

SELECT null,
sum(IIF(layer='key info',1,0)) AS [Key Info],
sum(IIF(layer='approaches',1,0)) AS [Approaches],
sum(IIF(layer='research',1,0)) AS [Research]
FROM resources
于 2013-06-20T10:42:54.473 回答
1

UNION 中的每个 SELECT 都应该具有相同数量的字段（在您的情况下为 4 个）。也许只是将“存根”字段添加到 SELECT 中，例如 NULL？

UNION
 SELECT
   NULL, -- <- STUB (for padding only)
   sum(IIF(layer='key info',1,0)) AS [Key Info],
   sum(IIF(layer='approaches',1,0)) AS [Approaches],
   sum(IIF(layer='research',1,0)) AS [Research]
FROM resources
UNION
于 2013-06-20T10:46:46.323 回答
1

您删除lw status并且没有选择任何内容： 

UNION
SELECT 'SUM',
sum(IIF(layer='key info',1,0)) AS [Key Info],
sum(IIF(layer='approaches',1,0)) AS [Approaches],
sum(IIF(layer='research',1,0)) AS [Research]
FROM resources
UNION 
<Next Query>
于 2013-06-20T10:40:51.373 回答