Java 当运行相同的查询时从 SQL 返回不同的结果

Question

我有一个用 Java (netbeans/uncanaccess) 编写的 SQL 语句，这是一个相当简单的 select 语句，其中包含来自一个 [=59 的一些 IIF 和 SUM =] 在我的数据库中。

当我运行 SQL 语句在 Access it returns 中得到正确的结果，但是当我试图运行它在 Java 时， returns 结果相似，但不完全相同。

Java代码

public int getActualMHDetails(String strNumber, String strYear, String strPeriod){
    String strSQLString = null;
    System.out.println("Getting cost details for: " + strNumber);
    try{

strSQLString = "SELECT tblExportCost.ProjDef, tblExportCost.Year,\n"
                        + "Sum(IIf([Per]=1,[Val/ObjCur],0)) AS Jan, Sum(IIf([Per]=2,[Val/ObjCur],0)) AS Feb, Sum(IIf([Per]=3,[Val/ObjCur],0)) AS Mar,\n"
                        + "Sum(IIf([Per]=4,[Val/ObjCur],0)) AS Apr, Sum(IIf([Per]=5,[Val/ObjCur],0)) AS May, Sum(IIf([Per]=6,[Val/ObjCur],0)) AS Jun,\n"
                        + "Sum(IIf([Per]=7,[Val/ObjCur],0)) AS Jul, Sum(IIf([Per]=8,[Val/ObjCur],0)) AS Aug, Sum(IIf([Per]=9,[Val/ObjCur],0)) AS Sep,\n"
                        + "Sum(IIf([Per]=10,[Val/ObjCur],0)) AS Oct, Sum(IIf([Per]=11,[Val/ObjCur],0)) AS Nov, Sum(IIf([Per]=12,[Val/ObjCur],0)) AS Dec\n" 
                        + "FROM tblExportCost\n" 
                        + "GROUP BY tblExportCost.ProjDef, tblExportCost.Year, tblExportCost.Year\n" 
                        + "HAVING (((tblExportCost.Year)= '" + strYear + "') AND ((tblExportCost.ProjDef)= 'T3415" + strNumber + "'))";

//SETTING PREPARED STATEMENT
        PreparedStatement preStatement = con.prepareStatement(strSQLString, ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);

        ResultSet rs = preStatement.executeQuery();

        rs.next();

        //IF CHECKS TO MAKE SURE RECORDS
        if(rs.getRow()==0){
            rs.close();      
            preStatement.close();
            return 3;
        }        

        strTest = rs.getString("Jan");

        System.out.println("Test Value: " + strTest); 

        intAMHCJan = rs.getInt("Jan");
        intAMHCFeb = rs.getInt("Feb");
        intAMHCMar = rs.getInt("Mar");
        intAMHCApr = rs.getInt("Apr");
        intAMHCMay = rs.getInt("May");
        intAMHCJun = rs.getInt("Jun");
        intAMHCJul = rs.getInt("Jul");
        intAMHCAug = rs.getInt("Aug");
        intAMHCSep = rs.getInt("Sep");
        intAMHCOct = rs.getInt("Oct");
        intAMHCNov = rs.getInt("Nov");
        intAMHCDec = rs.getInt("Dec");

        //CLOSES CONNECTIONS
        System.out.println("Database query successful; closing connections");
        rs.close();
        preStatement.close();            

        return 1;

    }catch(Exception ex){
        ex.printStackTrace();
        strEXMessage=ex.getMessage();
        return 2;
    }
}

访问码

SELECT tblExportCost.ProjDef, tblExportCost.Year,
Sum(IIf([Per]=1,[Val/ObjCur],0)) AS Jan, Sum(IIf([Per]=2,[Val/ObjCur],0)) AS Feb, Sum(IIf([Per]=3,[Val/ObjCur],0)) AS Mar,
Sum(IIf([Per]=4,[Val/ObjCur],0)) AS Apr, Sum(IIf([Per]=5,[Val/ObjCur],0)) AS May, Sum(IIf([Per]=6,[Val/ObjCur],0)) AS Jun,
Sum(IIf([Per]=7,[Val/ObjCur],0)) AS Jul, Sum(IIf([Per]=8,[Val/ObjCur],0)) AS Aug, Sum(IIf([Per]=9,[Val/ObjCur],0)) AS Sep,
Sum(IIf([Per]=10,[Val/ObjCur],0)) AS Oct, Sum(IIf([Per]=11,[Val/ObjCur],0)) AS Nov, Sum(IIf([Per]=12,[Val/ObjCur],0)) AS Dec
FROM tblExportCost
GROUP BY tblExportCost.ProjDef, tblExportCost.Year, tblExportCost.Year
HAVING (((tblExportCost.Year)= 2016) AND ((tblExportCost.ProjDef)= 'T34151234'))

我什至尝试保存 Access 查询并简单地使用

strSQLString = "SELECT * FROM qryTestJava";

但这也 returns 同样的错误结果。

结果

SQL

ProjDef     Year   Jan      Feb               Mar          Apr        May   
T34151234   2016  22358.1  18742.9  3443.33000000001    10251.03    12706.78

Java

ProjDef     Year   Jan      Feb         Mar        Apr        May   
T34151234   2016  22,329  18,714       3,420      10,226    12,684

我做了一些挖掘，发现舍入和 ucanacess 也有类似的问题 Here，但据报道它已在早期版本中修复。

我当前的ucanaccess版本是2.0.9.3

Answer 1

我能够在 UCanAccess 3.0.5 下重现您的问题。 IIf() 函数在作为

调用时似乎将双精度值截断为其整数值

SELECT IIf([Per]=1,[Val/ObjCur],0) AS ...

而当使用 0.0 作为数字文字值调用 IIf() 时，会正确返回整个双精度值，即

SELECT IIf([Per]=1,[Val/ObjCur],0.0) AS ...

因此您应该能够使用

检索正确的 SUM

strSQLString = "SELECT tblExportCost.ProjDef, tblExportCost.Year,\n"
                        + "Sum(IIf([Per]=1,[Val/ObjCur],0.0)) AS Jan, Sum(IIf([Per]=2,[Val/ObjCur],0.0)) AS Feb, Sum(IIf([Per]=3,[Val/ObjCur],0.0)) AS Mar,\n"
                        + "Sum(IIf([Per]=4,[Val/ObjCur],0.0)) AS Apr, Sum(IIf([Per]=5,[Val/ObjCur],0.0)) AS May, Sum(IIf([Per]=6,[Val/ObjCur],0.0)) AS Jun,\n"
                        + "Sum(IIf([Per]=7,[Val/ObjCur],0.0)) AS Jul, Sum(IIf([Per]=8,[Val/ObjCur],0.0)) AS Aug, Sum(IIf([Per]=9,[Val/ObjCur],0.0)) AS Sep,\n"
                        + "Sum(IIf([Per]=10,[Val/ObjCur],0.0)) AS Oct, Sum(IIf([Per]=11,[Val/ObjCur],0.0)) AS Nov, Sum(IIf([Per]=12,[Val/ObjCur],0.0)) AS Dec\n" 
                        + "FROM tblExportCost\n" 
                        + "GROUP BY tblExportCost.ProjDef, tblExportCost.Year\n" 
                        + "HAVING (((tblExportCost.Year)= '" + strYear + "') AND ((tblExportCost.ProjDef)= 'T3415" + strNumber + "'))";

Java 当运行相同的查询时从 SQL 返回不同的结果

Java returning different result from SQL when running identical query

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Java 当 运行 相同的查询时从 SQL 返回不同的结果

Java returning different result from SQL when running identical query

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netbeans

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Java 当运行相同的查询时从 SQL 返回不同的结果