SQL：將單行分成2行或3行

Question

我正在尋找將行分成2行或3行。這可能嗎？
我有一個表，顯示行情如下：

表名：行情

ID | NAME | BusCost | TaxiCost | TrainCost 
------------------------------------------- 
01 | Steve | NULL | 25  | NULL 
02 | Barry | 15  | 30  | NULL 
03 | Bob | 150  | 400  | 300 

但我想說明這樣的行情：

ID | Name | Cost 
------------------ 
01 | Steve | 25 
02 | Barry | 15 
02 | Barry | 30 
03 | Bob | 30 
03 | Bob | 100 
03 | Bob | 70 

我猜我我將需要使用某種UNION來做到這一點，但我很茫然。我對SQL相對比較陌生，並且希望任何人都能指向正確的方向。

我來（不是很緊密要麼）最接近的是這樣：

SELECT COST 
FROM 
(
SELECT BusCost AS COST FROM Quotes 
UNION 
SELECT TaxiCost AS COST FROM Quotes 
UNION 
SELECT TrainCost AS COST FROM Quotes 
) A 
GROUP BY COST 

SELECT id, name FROM Quotes 
UNION ALL 
SELECT COST 
FROM 
(
SELECT BusCost AS COST FROM Quotes 
UNION 
SELECT TaxiCost AS COST FROM Quotes 
UNION 
SELECT TrainCost AS COST FROM Quotes 
) A 
GROUP BY COST 

任何幫助將不勝感激。

Answer 1

SELECT * 
FROM (
     SELECT id 
     ,  Name 
     ,  BusCost as Cost 
     FROM Quotes 
     UNION ALL 
     SELECT id 
     ,  Name 
     ,  TaxiCost 
     FROM Quotes 
     UNION ALL 
     SELECT id 
     ,  Name 
     ,  TrainCost 
     FROM Quotes 
     ) AllCosts 
WHERE Cost IS NOT NULL 

的where子句刪除不具有成本，例如當TaxiCost是空行。使用union all而不是union：後者刪除重複的行。