选择查询选择语句

我甚至不知道我是否以正确的方式执行此查询。有一个Sandwiches表有7个字段，其中2个是组合框（Type和Bread）。选择查询选择语句

所以我提出，结合了所有组合框的值到一个查询，这样的查询：

SELECT TypesAndBreads.TBName, TypesAndBreads.Type 
FROM (SELECT [Sandwiches Types].[Sandwich Type] As TBName, "Sandwich Type" As Type 
    FROM [Sandwiches Types] 
UNION ALL 
    SELECT Breads.Bread As TBName, "Bread" As Type 
    FROM Breads) AS TypesAndBreads;

我拿到表的平值，现在我要统计所有在每个TypesAndBreads.TBName三明治。我有这个，只是为了确保它的工作原理与所有的三明治：

SELECT TypesAndBread.Type, TypesAndBread.TBName, 
     (SELECT Count(Sandwiches.[SandwichID]) As SandwichCount 
     FROM Sandwiches) As SandwichCount 
FROM TypesAndBread;

但我想引用里面的子查询当前Type和TBName。像这样的：

SELECT TypesAndBread.Type, TypesAndBread.TBName, 
     (SELECT Count(Sandwiches.[SandwichID]) As SandwichCount 
     FROM Sandwiches 
     WHERE Sandwiches.[TypesAndBread.Type] = Sandwiches.[TypesAndBread.TBName]) As SandwichCount 
FROM TypesAndBread;

但当然这是行不通的。我不认为这会，只是想尝试一下。我正在考虑使用VBA构建查询，当他们打开此查询将基于的报告时。

所以我想我的问题是：有没有办法引用子查询中当前选定的字段？还是有不同的方法来解决这个问题？

感谢您的帮助

编辑： 我的表结构是这样的：

Sandwiches的领域

| SandwichID | Name | Date Added | Chef | Sandwich Type | Bread | Reviewed By |

其中Sandwich Type和Bread是这些表的查阅字段：

Sandwiches Types的领域

| Sandwich Type |

Breads的领域

| Bread |

的TypesAndBreads查询相结合的三明治类型和面包表，但之所以说是为了让我可以得到所有的三明治伯爵那种类型或面包。像这样的结果：

+=============================================+ 
|  Type  | TBName | SandwichCount | 
+=============================================+ 
| Sandwich Type | Turkey Club |   10 | 
| Bread   | Italian  |    5 | 
| Bread   | Garlic  |    8 | 
+---------------------------------------------+

的例子结果的第一行basicly说，有10个三明治与三明治类型字段等于土耳其俱乐部纪录。

我希望能更好地解释它。

来源

2010-01-11 Tony L.

我发现这有点混乱。你可以发布你的表格结构和所需的输出吗？ – RedFilter 2010-01-11 18:24:45

我添加了表结构和一些所需的输出，希望有所帮助。感谢您的评论。 – 2010-01-11 20:04:17

不知道Access支持，但在大多数发动机（包括SQL Server）这就是所谓的相关子查询和正常工作：

SELECT TypesAndBread.Type, TypesAndBread.TBName, 
     (
     SELECT Count(Sandwiches.[SandwichID]) As SandwichCount 
     FROM Sandwiches 
     WHERE (Type = 'Sandwich Type' AND Sandwiches.Type = TypesAndBread.TBName) 
       OR (Type = 'Bread' AND Sandwiches.Bread = TypesAndBread.TBName) 
     ) As SandwichCount 
FROM TypesAndBread

这可以通过索引Type和Bread和分配更有效率子查询结果为UNION：

SELECT [Sandwiches Types].[Sandwich Type] As TBName, "Sandwich Type" As Type, 
     (
     SELECT COUNT(*) As SandwichCount 
     FROM Sandwiches 
     WHERE Sandwiches.Type = [Sandwiches Types].[Sandwich Type] 
     ) 
FROM [Sandwiches Types] 
UNION ALL 
SELECT [Breads].[Bread] As TBName, "Bread" As Type, 
     (
     SELECT COUNT(*) As SandwichCount 
     FROM Sandwiches 
     WHERE Sandwiches.Bread = [Breads].[Bread] 
     ) 
FROM [Breads]

来源

2010-01-11 18:24:00 Quassnoi

Jet/ACE一直支持相关的子查询。但是，它们在索引使用方面通常没有很好的优化。 – 2010-01-11 19:41:03

我过于复杂了。长时间休息和回来后，所需的输出可以通过这个简单的查询来实现：回答

SELECT Sandwiches.[Sandwich Type], Sandwich.Bread, Count(Sandwiches.[SandwichID]) AS [Total Sandwiches] 
FROM Sandwiches 
GROUP BY Sandwiches.[Sandwiches Type], Sandwiches.Bread;

谢谢，这帮助了我的思路。

来源

2010-01-11 20:58:48

选择查询选择语句

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