通过排除 Null 进行分组 - sql答案

【问题标题】：Group by excluding Null - tsql通过排除 Null 进行分组 - sql
【发布时间】：2013-02-14 12:36:19
【问题描述】：

我在下面有一个脚本：

    ;;WITH CTE AS
    (
        SELECT 
                RANK() OVER (PARTITION BY PortfolioID ORDER BY SUM(Percentage) DESC,MAX(SecurityName)) AS [Rank]
            ,   ReportingDate
            ,   PortfolioID
            ,   PortfolioNme
            ,   MAX(SecurityName)                               AS SecurityName
            ,   CAST(SUM(Percentage) AS DECIMAL(22,1))          AS [Weight]
            ,   SEDOL
            ,   MAX(ISIN)                                       AS ISIN
        FROM @Worktable as WT

        WHERE WT.IssueType2 <> '010' AND WT.IssueType2 <> '055' AND WT.IssueType1 <> '110' -- To remove CASH and FX and Collateral

        GROUP BY    WT.ReportingDate
                ,   WT.PortfolioID
                ,   WT.PortfolioNme
                ,   WT.SEDOL
    )

    SELECT 
          CONVERT(VARCHAR, ReportingDate, 103)  AS ReportingDate
        , PortfolioID                           AS FundCode
        , PortfolioNme                          AS FundName
        , SecurityName                          AS InstrumentName
        , [Rank]
        , [Weight]                              AS Percentage
        , SEDOL
        , ISIN
    FROM CTE

    WHERE [Rank] <= 10

    ORDER BY ReportingDate, PortfolioID, [Rank], [Weight] DESC

我按 SEDOL 进行分组，因为我想将相同的 SEDOL 组合在一起，但这会导致 NULLS 组合在一起。我尝试通过在 SEDOL 周围添加一个 MAX 来更改脚本并放置：

CASE 
    WHEN SEDOL IS NULL THEN SecurityName 
    ELSE SEDOL
END

在我的 GROUP BY 中但没有成功。

非常感谢任何帮助。

谢谢

【问题讨论】：

你可以尝试像 ISNULL(SEDOL,SecurityName) as Sese ... 并将 group by 更改为 group by WT.Sese
但我需要在最终选择中返回 SEDOLS，如果它为 null，我需要返回一个 null

标签： sql-server-2008 tsql group-by common-table-expression

【解决方案1】：

听起来您只想在 CTE WHERE 子句中添加 AND WT.SEDOL is not null

【讨论】：

【解决方案2】：

怎么样：

;;WITH CTE AS
    (
        SELECT 
                RANK() OVER (PARTITION BY PortfolioID ORDER BY SUM(Percentage) DESC,MAX(SecurityName)) AS [Rank]
            ,   ReportingDate
            ,   PortfolioID
            ,   PortfolioNme
            ,   MAX(SecurityName)                               AS SecurityName
            ,   CAST(SUM(Percentage) AS DECIMAL(22,1))          AS [Weight]
            ,   ISNULL(SEDOL, SecurityName) AS SEDOL
            ,   MAX(ISIN)                                       AS ISIN
        FROM @Worktable as WT

        WHERE WT.IssueType2 <> '010' AND WT.IssueType2 <> '055' AND WT.IssueType1 <> '110' -- To remove CASH and FX and Collateral

        GROUP BY    WT.ReportingDate
                ,   WT.PortfolioID
                ,   WT.PortfolioNme
                ,   ISNULL(WT.SEDOL, SecurityName)
    )

    SELECT 
          CONVERT(VARCHAR, ReportingDate, 103)  AS ReportingDate
        , PortfolioID                           AS FundCode
        , PortfolioNme                          AS FundName
        , SecurityName                          AS InstrumentName
        , [Rank]
        , [Weight]                              AS Percentage
        , SEDOL
        , ISIN
    FROM CTE

    WHERE [Rank] <= 10

    ORDER BY ReportingDate, PortfolioID, [Rank], [Weight] DESC

【讨论】：

这就是我一直在尝试的。由于某种原因，我无法理解 ISNULL 不起作用，即使我删除了所有聚合和 group by 我仍然无法让 ISNULL 工作。
我将 ISNULL(WT.SEDOL, SecurityName) 更改为： CASE WHEN SEDOL = '' THEN SecurityName ELSE SEDOL END 感谢您的帮助，我知道这很容易