无法计算嵌套子查询的结果差异并出现语法错误

Question

如果我单独运行每个查询，我会得到结果，但是，当我尝试执行嵌套查询时，我会继续遇到语法错误。

消息 102，第 15 级，状态 1，第 10 行
')' 附近的语法不正确。

这是我正在尝试运行的查询的副本。

Select 
    P.Part_Type, P.Number, P.mold, 
    dbo.tbl_Msmt_Data.Result as Val1, 
    dbo.tbl_Msmt_Data.Result as Val2, 
    ((Val1 - Val2) / 60) As DIFF
From 
    (Select 
         P.Part_Type, P.Number, P.mold, dbo.tbl_Msmt_Data.Result as Val1
     from
         dbo.tbl_Parts P 
     inner join
         dbo.tbl_Msmt_Data on P.Parts_ID = dbo.tbl_Msmt_Data.Part
     where 
         (P.Part_Type = 'Shell PS') 
         and (dbo.tbl_Msmt_Data.Msmt_Spec = 7327)

     union all

     select 
         P.Part_Type, P.Number, P.mold, dbo.tbl_Msmt_Data.Result as Val2
     from
         dbo.tbl_Parts P 
     inner join
         dbo.tbl_Msmt_Data on P.Parts_ID = dbo.tbl_Msmt_Data.Part
     where 
         (P.Part_Type = 'Shell PS') 
         and (dbo.tbl_Msmt_Data.Msmt_Spec = 7326)
)

我已尝试删除零件表的别名。我尝试在第二个查询中只选择 Val2。在这一点上，我不确定我还能做什么。

这是 Val1 的结果示例

这是来自 tbl_parts 和 tbl_msmt_data 的数据样本

Answer 1

试试这个：

SELECT 
    Part_Type, 
    Number, 
    mold, 
    Val1, 
    Val2, 
    ( ( Val1 - Val2 ) / 60 ) AS DIFF -- possible divide by zero exception!
FROM (

    SELECT 
        P.Part_Type, P.Number, P.mold, ISNULL ( M.Result, 0 ) AS Val1, 0 AS Val2
    FROM dbo.tbl_Parts AS P 
    INNER JOIN dbo.tbl_Msmt_Data AS M
        ON P.Parts_ID = M.Part
    WHERE 
        P.Part_Type = 'Shell PS' 
        AND M.Msmt_Spec = 7327
    UNION ALL
    SELECT 
        P.Part_Type, P.Number, P.mold, 0 AS Val1, ISNULL ( M.Result, 0 ) AS Val2
    FROM dbo.tbl_Parts AS P 
    INNER JOIN dbo.tbl_Msmt_Data AS M
        ON P.Parts_ID = M.Part
    WHERE 
        P.Part_Type = 'Shell PS'
        AND M.Msmt_Spec = 7326

) AS MyTable;

更新：

我不得不将答案标记为未解决，因为我发现了我之前没有看到的解决方案的问题。当它进行查询时，它将为每个数字显示两个条目，一行将 Val 1 为空，而 Val 2 有一个数字。

要为 Msmt_Spec 值 7326 和 7327 返回单行，您可以执行以下操作：

SELECT 
    Part_Type, 
    Number, 
    Mold, 
    Val1, 
    Val2, 
    ( ( Val1 - Val2 ) / 60 ) AS DIFF
FROM (

    SELECT
        P.Part_Type, P.Number, P.Mold
        , MAX ( CASE WHEN M.Msmt_Spec = 7327 THEN M.Result ELSE 0 END ) AS Val1
        , MAX ( CASE WHEN M.Msmt_Spec = 7326 THEN M.Result ELSE 0 END ) AS Val2
    FROM dbo.tbl_Parts AS P
    INNER JOIN dbo.tbl_Msmt_Data AS M
        ON P.Parts_ID = M.Part
    WHERE 
        P.Part_Type = 'Shell PS'
        AND M.Msmt_Spec IN ( 7326, 7327 )
    GROUP BY
        Part_Type, Number, Mold

) AS MyTable
ORDER BY
    Part_Type, Number;

我的测试结果（有限的数据集）返回如下：

+-----------+--------+------+------+------+------+
| Part_Type | Number | Mold | Val1 | Val2 | DIFF |
+-----------+--------+------+------+------+------+
| Shell PS  |   2200 |    2 | 1000 |  847 |    2 |
| Shell PS  |   2201 |    3 | 1608 | 1500 |    1 |
| Shell PS  |   2202 |    1 |  225 |   45 |    3 |
| Shell PS  |   2203 |    4 | 1015 |  909 |    1 |
| Shell PS  |   2204 |    2 | 1615 | 1447 |    2 |
+-----------+--------+------+------+------+------+

这是您想要实现的目标吗？