MySQL表联盟和新列

Question

举两个在下表中，

电话表：

PID NAME 
1001 iphone 
1002 samsung 
1003 sony 

PC表：

CID NAME 
1001 HP 
1002 XPS 

我怎样才能得到结果表？

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

我认为这应该使用UNION，但如何处理TYPE？

Answer 1

如果你想重复结果，你应该使用UNION ALL，否则你可以使用UNION消除重复的值。

您的查询会是这样，

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

这两个表中选择所有记录。

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

使用此查询：

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