聯合SQL總計行

我想從SUM中的不同SQL查詢中獲取兩行SUM，這可能嗎？所有我能達到的是兩個單獨的行，但我不能SUM他們，數據庫引擎讓我告訴，*）FROM（旁邊的部分）FROM附近的語法中有錯誤...聯合SQL總計行

這裏的查詢：

SELECT * FROM 

(SELECT COUNT(*) as cntclients                        
    FROM                              
    (SELECT DISTINCT clientkey AS clients                      
     FROM <table> 
    WHERE <conditions...>)                             
    ) AS clients                            
) cntclients 

UNION 

(SELECT SUM(occurrences) AS cntclientsad              
    FROM <table2> 
    WHERE <conditions...>          
)

這引發了我，例如：

cntclients 
---------- 
901 
50

添加SELECT SUM（*）FROM而不是SELECT * FROM在第一線，和周圍有括號中的兩個查詢只是拋出我提到的錯誤...

我想

cntclients <- or whatever name... 
---------- 
951

任何想法，這筆錢應該如何工作？

來源

2012-02-22 Javier Novoa C.

你實際上並不需要使用這個UNION - 你可以把它們相加手動：

SELECT a.countKey + b.sumOccur as total 
FROM (SELECT COUNT(DISINCT clientkey) as countKey 
     FROM <table> 
     WHERE <conditions>) as a 
CROSS JOIN (SELECT SUM(occurrences) as sumOccur 
      FROM <table2> 
      WHERE <conditions>) as b

來源

2012-02-22 23:58:38

您可以使用'CROSS JOIN'（不帶'ON'）代替'JOIN ... ON 1 = 1'。 – 2012-02-23 00:13:25

@ypercube - 謝謝 - 我經常不需要真正的笛卡爾產品，所以我忘了它。 – 2012-02-23 00:50:07

select SUM(cntcol) 
from 
(
    select count(*) as cntcol from sometables 
    union all 
    select SUM(occurrances) as cntcol from somemoretables 
) ctquery

來源

2012-02-23 00:00:05

你不需要'GROUP BY'來使用'SUM（）'嗎？ – 2012-02-23 00:02:45

沒有。如果你想總結所有行，你爲什麼需要任何種類的分組？ – 2012-02-23 00:05:10

如果你想用UNION堅持，你可以這樣寫：

SELECT sum(c.cntclients) as Totalcntclients 
FROM 
(

    SELECT COUNT(*) as cntclients                        
    FROM                              
    (SELECT DISTINCT clientkey AS clients                      
     FROM <table> 
    WHERE <conditions...>                             
    ) AS clients                            

    UNION 

    SELECT SUM(occurrences) AS cntclientsad              
    FROM <table2> 
    WHERE <conditions...>          

) c

來源

2012-02-23 00:00:49 Taryn

您還可以使用：

SELECT 
    (SELECT COUNT(DISTINCT clientkey) as countKey 
     FROM <table> 
     WHERE <conditions> 
    ) 
    + 
    (SELECT SUM(occurrences) as sumOccur 
     FROM <table2> 
     WHERE <conditions> 
    ) 
    AS total

來源

2012-02-23 00:20:06

有類似的問題，並感謝您的簡單回答我可以寫一個適當的查詢。謝謝。仍然，我想知道，爲什麼當我替換）+（爲聯合在查詢dosn't工作正常？文檔中沒有給我提供線索 – 2012-05-02 19:48:46

如果你這樣做替換你有一個子查詢：'（SELECT cnt ... UNION SELECT ...）'這是一個有1列，2行的表格，你可以使用'SELECT SUM（cnt）FROM（SELECT cnt ... UNION SELECT ...）AS g'。沒有額外的聚合（SUM），因爲子查詢返回一列1行，你可以把這些子查詢放在選擇列表中。 – 2012-05-02 21:17:55

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