假设我有一张这样的桌子
id | device | cmd | value |
------+----------------+-------+---------
id = unique row ID
device = device identifier (mac address)
cmd = some arbitrary command
value = value of corresponding command
我想以某种方式自加入此表以获取特定设备的特定命令及其相应值。
我不想只是SELECT cmd,value FROM table WHERE device='00:11:22:33:44:55';
说我想要的值对应于getname
and getlocation
命令。我想要输出类似的东西
mac | name | location
--------------------+-----------+------------
00:11:22:33:44:55 | some name | somewhere
我的 sql fu 很漂亮。我一直在尝试不同的组合,例如SELECT a.value,b.value FROM table AS a INNER JOIN table AS b ON a.device=b.device
但我一事无成。
谢谢你的帮助。
SELECT a.value AS thisval ,b.value AS thatval
FROM table AS a JOIN table AS b USING (device)
WHERE a.command='this' AND b.command='that';
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