mysql表联合和新列

Question

提供以下两个表格，

电话表：

 PID   NAME
1001 iphone
1002 samsung
1003 sony

pc table：

 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，但是如何处理TYPE？

Answer 1

如果你想复制结果，你应该使用UNION ALL，否则你可以使用UNION来消除重复的值。

您的查询将是这样的，

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

这将从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;