MySQL表聯盟和新列

Question

舉兩個在下表中，

電話表：

PID NAME 
1001 iphone 
1002 samsung 
1003 sony 

PC表：

CID NAME 
1001 HP 
1002 XPS 

我怎樣才能得到結果表？

DID TYPE NAME 
1001 PHONE iphone 
1002 PHONE samsung 
1003 PHONE sony 
1001 PC HP 
1002 PC XPS 

我認爲這應該使用UNION，但如何處理TYPE？

Answer 1

如果你想重複結果，你應該使用UNION ALL，否則你可以使用UNION消除重複的值。

您的查詢會是這樣，

select pid as DID,'PHONE' as TYPE,name from phone 
UNION all 
select CID as DID,'PC' as TYPE,name from PC; 

這兩個表中選擇所有記錄。

Answer 2

SELECT PID AS DID, 'PHONE' AS TYPE, NAME FROM Phone 
UNION ALL 
SELECT CID AS DID, 'PC' AS TYPE, NAME FROM PC; 

Answer 3

使用此查詢：

select pid as DID,'PHONE' as TYPE, name from phone 
UNION 
select cid as DID,'PC' as TYPE, name from PC;