Question

这几乎有用......

SELECT 
    dbo.ObjectThumb.dotID, dbo.ObjectThumb.doID, 
    dbo.ObjectThumb.dotWidth, dbo.ObjectThumb.dotHeight, 
    dbo.Object.doWidth, dbo.Object.doHeight, 
    (CAST(dotWidth AS FLOAT) / CAST(doWidth AS FLOAT)) AS 'widthRatio', 
    (CAST(dotHeight AS FLOAT) / CAST(doHeight AS FLOAT)) AS 'heightRatio', 
    (SELECT Max(v) FROM (VALUES (widthRatio), (heightRatio)) AS value(v)) AS MaxRatio 
FROM 
   dbo.ObjectThumb 
INNER JOIN 
   dbo.Object ON Object.doID = ObjectThumb.doID

服务器返回错误：

列名称widthRatio无效列名称heightRatio无效

这些列在外部选择中计算。如果我引用两个非计算列（例如doID＆amp; dotID），则运行我的查询。

我想我的内部选择的语法搞砸了。这将在SQL Server 2008 R2（v10.50.2550）上运行。

我离该内部列的正确语法不远。例如，如果我运行

SELECT * 
FROM (VALUES (1,2), (5,3), (1,4)) AS tableOfValues (columnName1, ColumnName2)

我得到了

1 2
5 3
1 4

我很感激帮助使用语法来引用外部select中的计算列。如果你能告诉我正确的英语来表示内部选择，外部选择和计算列，那将是一个奖励！

Answer 1

要理解的重要一点是，你的逻辑不会起作用。您无法在主查询中选择一个值，在这种情况下，来自子选择或内联查询的widthRatio和heightRatio，因为它超出了该查询的范围。知道你想要做的是创建一个你将加入主查询的内联查询。

您的内联查询应该看起来像这样

Select ObjectThumb.doID As 'LinkID',
    (CAST(dotWidth AS FLOAT) / CAST(doWidth AS FLOAT)) AS 'Ratio'
From ObjectThumb 
    INNER JOIN Object ON Object.doID = ObjectThumb.doID

Union

Select ObjectThumb.doID,
    (CAST(dotHeight AS FLOAT) / CAST(doHeight AS FLOAT))
From ObjectThumb 
    INNER JOIN Object ON Object.doID = ObjectThumb.doID

然后，您可以像这样加入您的内联查询

SELECT ObjectThumb.dotID, 
       ObjectThumb.doID, 
       ObjectThumb.dotWidth, 
       ObjectThumb.dotHeight, 
       Object.doWidth, 
       Object.doHeight, 
       (CAST(dotWidth AS FLOAT) / CAST(doWidth AS FLOAT)) AS 'widthRatio', 
       (CAST(dotHeight AS FLOAT) / CAST(doHeight AS FLOAT)) AS 'heightRatio',
       Max(AllRatioTable.Ratio) As MaxRatio
From ObjectThumb 
    INNER JOIN Object ON Object.doID = ObjectThumb.doID
    Inner Join (Select ObjectThumb.doID As 'LinkID',
                    (CAST(dotWidth AS FLOAT) / CAST(doWidth AS FLOAT)) AS 'Ratio'
                From ObjectThumb 
                    INNER JOIN Object ON Object.doID = ObjectThumb.doID

                Union

                Select ObjectThumb.doID,
                    (CAST(dotHeight AS FLOAT) / CAST(doHeight AS FLOAT))
                From ObjectThumb 
                    INNER JOIN Object ON Object.doID = ObjectThumb.doID
                ) As AllRatioTable
        On ObjectThumb.doID = AllRatioTable.LinkID
Group by ObjectThumb.dotID, 
         ObjectThumb.doID, 
         ObjectThumb.dotWidth, 
         ObjectThumb.dotHeight, 
         Object.doWidth, 
         Object.doHeight

关于如何调用您的子选择的主题，请参见此处：

http://www.allinterview.com/showanswers/81062/what-is-different-between-inline-query-subquery-corelated-query.html

SQL内部选择参考计算值

1 个答案: