我可以在最大/最小值函數中使用case與case和？

我想總結一個案例的發生。我試圖使用案件陳述的總和，但我得到這個錯誤，它如何解決？我可以在最大/最小值函數中使用case與case和？

Msg 130, Level 15, State 1, Line 3 
Cannot perform an aggregate function on an expression containing an aggregate or a subquery.

我的代碼示例：

select 
sum(case when cast(max(ptl.RowDate)as int) = cast(Min(ptl.RowDate) as int) then 1 else 0 end) 
,DATEPART(WEEK, rowdate) week_ 
from m.dbo.tblLog ptl (nolock) 
where rowdate > GETDATE()-91 
group by DATEPART(WEEK, rowdate)

更新：基於評論：我想數着被訪問的網頁不同的用戶只once.I想基於每週獲得的計數大體時間。

來源

2016-07-26 mql4beginner

你不能那樣做。你需要重新思考並改變你的邏輯。提到你想要完成的事情。 –

這個數字甚至會做什麼？無論如何，每週只有一行，總和爲1或0。 –

請提供樣本數據和期望的結果。非工作查詢並不能傳達你真正想做的事情。 –

您不能在另一箇中使用聚合函數。您需要使用子查詢或CTE：

SELECT SUM(something) as s, 
     week_ 
FROM (
    select case when cast(max(ptl.RowDate)as int) = cast(Min(ptl.RowDate) as int) then 1 else 0 end as something, 
      DATEPART(WEEK, rowdate) week_ 
    from m.dbo.tblLog ptl (nolock) 
    where rowdate > GETDATE()-91 
    group by DATEPART(WEEK, rowdate) 
    ) as res 
GROUP BY week_

來源

2016-07-26 12:20:00 gofr1

替代的方式來查詢

SELECT SUM(CASE WHEN CAST(MaxRowDate AS INT) = cast(MinRowDate AS INT) THEN 1 ELSE 0 END) 
week_ 
FROM 
(

    SELECT MAX(ptl.RowDate) MaxRowDate,MIN(ptl.RowDate) MinRowDate,DATEPART(WEEK, rowdate) week_ 
    FROM m.dbo.tblLog ptl (NOLOCK) 
    WHERE rowdate > GETDATE()-91 
    GROUP BY DATEPART(WEEK, rowdate) 
)M 
GROUP BY week_

來源

2016-07-26 12:23:55

如果你只是想要一個標誌，你爲什麼要一個sum()：

select (case when cast(max(ptl.RowDate)as int) = cast(Min(ptl.RowDate) as int) 
      then 1 else 0 
     end) as OneValueFlag, 
     DATEPART(WEEK, rowdate) as week_ 
from m.dbo.tblLog ptl (nolock) 
where rowdate > GETDATE() - 91 
group by DATEPART(WEEK, rowdate);

價值會被轉換爲日期的原因也完全不清楚：

select (case when max(ptl.RowDate) = Min(ptl.RowDate) 
      then 1 else 0 
     end) as OneValueFlag, 
     DATEPART(WEEK, rowdate) as week_ 
from m.dbo.tblLog ptl (nolock) 
where rowdate > GETDATE() - 91 
group by DATEPART(WEEK, rowdate);

來源

2016-07-26 12:24:01

我可以在最大/最小值函數中使用case與case和？

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