如何仅从 T-SQL 中的一列计算时间？

Question

目前，我在下面有这个查询，它产生了很棒的结果，但是，我正在尝试计算 SiteID 的总数（无论查询中的其他因素如何）。

这是我目前的查询：

SELECT 
    TotalCharts ,
    SiteID ,
    Type,
    CASE
        WHEN TotalCharts BETWEEN 1 AND 4 THEN '1-4 Charts'  
        WHEN TotalCharts BETWEEN 5 AND 9 THEN '5-9 Charts'  
        WHEN TotalCharts BETWEEN 10 AND 24 THEN '10-24 Charts'  
        WHEN TotalCharts BETWEEN 25 AND 49 THEN '25-49 Charts'  
        WHEN TotalCharts BETWEEN 50 AND 99 THEN '50-99 Charts'  
        WHEN TotalCharts BETWEEN 100 AND 249 THEN '100-249 Charts'  
        WHEN TotalCharts BETWEEN 250 AND 499 THEN '250-499 Charts'  
        WHEN TotalCharts BETWEEN 500 AND 1000 THEN '500-1000 Charts'  
        WHEN TotalCharts > 1000 THEN 'Greater 1000'
    END AssignmentType,
    CASE
        WHEN TotalCharts BETWEEN 1 AND 4 THEN '1'  
        WHEN TotalCharts BETWEEN 5 AND 9 THEN '2'  
        WHEN TotalCharts BETWEEN 10 AND 24 THEN '3'  
        WHEN TotalCharts BETWEEN 25 AND 49 THEN '4'  
        WHEN TotalCharts BETWEEN 50 AND 99 THEN '5'  
        WHEN TotalCharts BETWEEN 100 AND 249 THEN '6'  
        WHEN TotalCharts BETWEEN 250 AND 499 THEN '7'  
        WHEN TotalCharts BETWEEN 500 AND 1000 THEN '8'  
        WHEN TotalCharts > 1000 THEN '9'
    END AssignmentTypeIndex
FROM (
    SELECT
    COUNT(c.ChartID) TotalCharts,
    c.SiteID, 
    CASE WHEN ChartRetrievalMethodID IS NULL THEN wfseg.SiteEventGroupID
ELSE ChartRetrievalMethodID END as Type
FROM
    dbo.Sites s 
    INNER JOIN dbo.Charts c ON s.SiteID = c.SiteID
    LEFT JOIN dbo.ChartRetrievalInformation cri ON c.ChartID=cri.ChartID
    LEFT JOIN dbo.WFSiteEvents wfse ON s.SiteID = wfse.SiteID AND EventStatusID IN (1,2)
    LEFT JOIN dbo.WFSiteEventTypes wfset ON wfse.EventTypeID = wfset.EventTypeID
    LEFT JOIN dbo.WFSiteEventGroups wfseg ON wfset.SiteEventGroupID = wfseg.SiteEventGroupID
WHERE
    c.SiteID <> 110
    and s.ProjectID=160
GROUP BY
    c.SiteID, 
    CASE WHEN ChartRetrievalMethodID IS NULL THEN wfseg.SiteEventGroupID
ELSE ChartRetrievalMethodID END
) d
ORDER BY SiteID

所以现在它正在显示单个站点 ID，我想显示完整的站点 ID 计数

但是，我认为这里真正使用count(distinct siteID) 的棘手部分是因为同一站点ID 有包含各种信息的行。示例：

TotalCharts | SiteID | SiteEventGroupID | AssignmentType | AssignmentTypeIndex
-------------------------------------------------------------------------------
9           | 12345  | 4                | 5-9 Charts     | 2
-------------------------------------------------------------------------------
1           | 12345  | 3                | 1-4 Charts     | 1 

因此，在这种情况下，同一个 SiteID 有两个不同的行，我只想计算这个特定的 SiteID，而不考虑其他信息。因此，我希望它只计算一次，而不是计算这个 SiteID 两次。

有没有一种方法可以让我只计算那个特定的列？

Answer 1

在这种情况下，您需要的是一个窗口函数。 下面是 TSQL 窗口函数的参考：http://msdn.microsoft.com/en-ca/library/ms189461.aspx

修改现有代码块：

SELECT
    TotalCharts,
    SiteID,
    Type, 
    AssignmentType,
    AssignmentTypeIndex,
    COUNT(SiteID) OVER (PARTITION BY SiteID) NumRowsbySite
FROM(
    SELECT 
        TotalCharts ,
        SiteID,     
        Type,
        CASE
            WHEN TotalCharts BETWEEN 1 AND 4 THEN '1-4 Charts'  
            WHEN TotalCharts BETWEEN 5 AND 9 THEN '5-9 Charts'  
            WHEN TotalCharts BETWEEN 10 AND 24 THEN '10-24 Charts'  
            WHEN TotalCharts BETWEEN 25 AND 49 THEN '25-49 Charts'  
            WHEN TotalCharts BETWEEN 50 AND 99 THEN '50-99 Charts'  
            WHEN TotalCharts BETWEEN 100 AND 249 THEN '100-249 Charts'  
            WHEN TotalCharts BETWEEN 250 AND 499 THEN '250-499 Charts'  
            WHEN TotalCharts BETWEEN 500 AND 1000 THEN '500-1000 Charts'  
            WHEN TotalCharts > 1000 THEN 'Greater 1000'
        END AssignmentType,
        CASE
            WHEN TotalCharts BETWEEN 1 AND 4 THEN '1'  
            WHEN TotalCharts BETWEEN 5 AND 9 THEN '2'  
            WHEN TotalCharts BETWEEN 10 AND 24 THEN '3'  
            WHEN TotalCharts BETWEEN 25 AND 49 THEN '4'  
            WHEN TotalCharts BETWEEN 50 AND 99 THEN '5'  
            WHEN TotalCharts BETWEEN 100 AND 249 THEN '6'  
            WHEN TotalCharts BETWEEN 250 AND 499 THEN '7'  
            WHEN TotalCharts BETWEEN 500 AND 1000 THEN '8'  
            WHEN TotalCharts > 1000 THEN '9'
        END AssignmentTypeIndex
    FROM (
        SELECT
        COUNT(c.ChartID) TotalCharts,
        c.SiteID, 
        CASE WHEN ChartRetrievalMethodID IS NULL THEN wfseg.SiteEventGroupID
    ELSE ChartRetrievalMethodID END as Type
    FROM
        dbo.Sites s 
        INNER JOIN dbo.Charts c ON s.SiteID = c.SiteID
        LEFT JOIN dbo.ChartRetrievalInformation cri ON c.ChartID=cri.ChartID
        LEFT JOIN dbo.WFSiteEvents wfse ON s.SiteID = wfse.SiteID AND EventStatusID IN (1,2)
        LEFT JOIN dbo.WFSiteEventTypes wfset ON wfse.EventTypeID = wfset.EventTypeID
        LEFT JOIN dbo.WFSiteEventGroups wfseg ON wfset.SiteEventGroupID = wfseg.SiteEventGroupID
    WHERE
        c.SiteID <> 110
        and s.ProjectID=160
    GROUP BY
        c.SiteID, 
        CASE WHEN ChartRetrievalMethodID IS NULL THEN wfseg.SiteEventGroupID
    ELSE ChartRetrievalMethodID END
    ) d
    ORDER BY SiteID) a