用常量變量選擇查詢

Question

我需要選擇一個表列值和一些常量變量。例如，

SQL表：

Key KeyName 
------------- 
1 Normal 
2 Basic 
3 Super 

恆值是R1，R2，R3，R4。

輸出結果作爲單柱：

Normal R1 
Normal R2 
Normal R3 
Normal R4 
Basic R1 
Basic R2 
. 
. 
. 
Super R4 

欣賞任何建議。謝謝。

Answer 1

試試這個：

SELECT 
    T.KeyName, 
    TT.ConstValues 
FROM Tbl T 
    CROSS JOIN 
    (VALUES ('R1'), ('R2'), ('R3'), ('R4')) TT(ConstValues) 

SQL FIDDLE DEMO

Answer 2

SELECT KeyName, Value = CASE WHEN [number] = 1 THEN 'R1' 
          WHEN [number] = 2 THEN 'R2' 
          WHEN [number] = 3 THEN 'R3' 
          WHEN [number] = 4 THEN 'R4' 
          ELSE '' 
         END 
FROM (SELECT KeyName, ROW_NUMBER OVER (PARTITION BY KeyName 
             ORDER BY KeyName) AS [number] 
     FROM MyTable) A 

Answer 3

您需要將常數值表示爲結果集，然後通過從中選擇兩個值來獲得笛卡爾乘積。例如：

WITH ConstantValues AS 
(
    SELECT 'R1' AS ConstantValue 
    UNION ALL 
    SELECT 'R2' 
    UNION ALL 
    SELECT 'R3' 
    UNION ALL 
    SELECT 'R4' 
) 

SELECT t.KeyName, c.ConstantValue 
FROM SqlTable t, ConstantValues c; 

如果你想每對要表示成一個結果，那麼你可以使用SELECT t.KeyName + ' ' + c.ConstantValue AS ResultColumn代替。