SQL查詢，聯盟訂購就像一棵樹

Question

你好，我有一個像

SELECT 4 AS sortf,XX FROM Table GROUP BY Y 
UNION 
SELECT 1 AS sortf,XX FROM Table GROUP BY Y 
UNION 
SELECT 2 AS sortf,XX FROM Table GROUP BY Y 
UNION 
SELECT 3 AS sortf,XX FROM Table GROUP BY Y 
ORDER BY 3,2 

我的問題查詢爲該線2和3 AR沒有下令像一棵樹。我嘗試了一些其他組合，但它沒有奏效。

Answer 1

，如果你想按數字排序的數據集把你的代碼和工會成一個公共表表達式和使用ROW_NUMBER（）函數產生行號，這樣的事情：

WITH CTE 
AS 
(
    SELECT 4 AS sortf, productid FROM Production.Products 
    UNION 
    SELECT 1 AS sortf,productid FROM Production.Products 
    UNION 
    SELECT 2 AS sortf,productid FROM Production.Products 
    UNION 
    SELECT 3 AS sortf,productid FROM Production.Products 
) 
SELECT *, ROW_NUMBER() OVER (ORDER BY productid) AS SortOrder 
FROM CTE 
ORDER BY SortOrder