Question

我有一张表[tblFull1 04WoodsideTransportV335]，所有数据都来自。我想获得[数据位置]和[load_case]，其中压力是Max，Min或Abs。它适用于Max和Min。 但由于某种原因，它不适用于Abs 。它在ms Access 2013中运行。我使用vba以编程方式生成查询。

Abs和max，min运算符之间是否有任何区别使它无效？

当Abs查询运行时，由于某种原因它会广告“As Expr1”，为什么会这样做呢？

我知道SQL看起来很糟糕，但它确实有效。如果您对如何改进有任何建议，请告诉我。

抱歉我的英语不好，我是挪威人。

具有MAX功能的SQL：

SELECT DISTINCT 
    t1.[load_case], t2.[Data Location] AS Nodenr, 
    t2.[MaxOfHoop Stress N/mm^2]
FROM 
    [tblFull1 04WoodsideTransportV335] AS t1,
    (SELECT 
         [tblFull1 04WoodsideTransportV335].[Data Location],
         MAX([tblFull1 04WoodsideTransportV335].[Hoop Stress N/mm^2]) AS [MaxOfHoop Stress N/mm^2]
     FROM 
         [tblFull1 04WoodsideTransportV335]
     GROUP BY 
         [tblFull1 04WoodsideTransportV335].[Data Location]
     HAVING ((([tblFull1 04WoodsideTransportV335].[Data Location])
        In (SELECT [Data Location]
            FROM [tblFull1 04WoodsideTransportV335]
            GROUP BY [Data Location]
            HAVING Count(*) > 1)) 
       AND ((MAX([tblFull1 04WoodsideTransportV335].[Hoop Stress N/mm^2])) Is Not Null))
     ORDER BY 
         [tblFull1 04WoodsideTransportV335].[Data Location]) AS t2
WHERE 
    ((t1.[Hoop Stress N/mm^2]) = [t2].[MaxOfHoop Stress N/mm^2])
ORDER BY 
    t1.[load_case] DESC;

带Abs功能的SQL：

SELECT DISTINCT 
    t1.load_case, t2.[Data Location] AS Nodenr, 
    t2.[AbsOfHoop Stress N/mm^2] AS Expr1
FROM 
    [tblFull1 04WoodsideTransportV335] AS t1,
    (SELECT 
         [tblFull1 04WoodsideTransportV335].[Data Location],
         ABS([tblFull1 04WoodsideTransportV335].[Hoop Stress N/mm^2]) AS[AbsOfHoop Stress N/mm^2]
     FROM [tblFull1 04WoodsideTransportV335]
     GROUP BY [tblFull1 04WoodsideTransportV335].[Data Location]
     HAVING ((([tblFull1 04WoodsideTransportV335].[Data Location])
                In (SELECT [Data Location]
                    FROM [tblFull1 04WoodsideTransportV335] 
                    GROUP BY [Data Location]
                    HAVING Count(*) > 1)) 
        AND ((ABS([tblFull1 04WoodsideTransportV335].[Hoop Stress N/mm^2])) Is Not Null))
     ORDER BY 
         [tblFull1 04WoodsideTransportV335].[Data Location]) AS t2
WHERE 
    (((t1.[Hoop Stress N/mm^2])=[t2].[AbsOfHoop Stress N/mm^2]))
ORDER BY 
    t1.load_case DESC;

Answer 1

在SQL中，在“HAVING”语句中，您只能使用“GROUP BY”中定义的列。对于其他列，您必须在聚合函数中使用，它们是： - AVG（） - 返回平均值 - COUNT（） - 返回行数 - FIRST（） - 返回第一个值 - LAST（） - 返回最后一个值 - MAX（） - 返回最大值 - MIN（） - 返回最小值 - SUM（） - 返回总和

为什么我的sql在使用Max函数时不能使用Abs函数？

1 个答案: