如何將兩個表（具有相同的模式）合併到一個具有不同值並指示每行來自哪個表的表中？

Question

假設我在SQL兩個表：

Table_Alpha Table_Bravo 
Id | Name  Id | Name 
---+------ ---+----- 
1 | Alice  1 | Charlie 
2 | Bob  2 | Bob 
3 | Charlie 3 | Dorothy 

我想這兩個表合併成一個單一的表，避免重複和跟蹤其表的每個名字從像這樣來了：

Result 
Name | Alpha | Bravo 
-------+-------+------ 
Alice | 1 | 0 
Bob | 1 | 1 
Charlie| 1 | 1 
Dorothy| 0 | 1 

我想，我想要的查詢將是這個樣子：

SELECT Name, 1 AS Alpha, 0 AS Bravo FROM Table_Alpha 
UNION 
SELECT Name, 0 AS Alpha, 1 AS Bravo FROM Table_Bravo; 

然而，上面的查詢將返回兩行對每個南e出現在兩張表中。我該如何編寫查詢，以便爲每個不同的名稱返回一行？

Answer 1

這項工作？

SELECT DISTINCT Name, sum(Alpha) as 'Alpha', sum(Bravo) as 'Bravo' 
FROM (
    SELECT Name, 1 as Alpha, 0 as Bravo from Table_Alpha 
    UNION 
    SELECT Name, 0 as Alpha, 1 as Bravo from Table_Bravo 
) X 
GROUP BY Name 

Answer 2

您可以使用FULL JOIN如果Name列沒有重複，沒有GROUP BY需要：

SELECT 
    COALESCE(a.Name, b.Name), 
    CASE WHEN a.Name IS NOT NULL THE 1 ELSE 0 END AS Alpha, 
    CASE WHEN b.Name IS NOT NULL THE 1 ELSE 0 END AS Bravo 
FROM 
    Table_Alpha AS a 
    FULL JOIN 
    Table_Bravo AS b 
     ON a.Name = b.Name ; 

如果有重複：

SELECT 
    COALESCE(a.Name, b.Name), 
    COUNT(a.Name) AS Alpha, 
    COUNT(b.Name) AS Bravo 
FROM 
    Table_Alpha AS a 
    FULL JOIN 
    Table_Bravo AS b 
     ON a.Name = b.Name 
GROUP BY 
    COALESCE(a.Name, b.Name) ;