基于另一个表的条件在一个MySQL表中查找条目

select distinct(hardware_name) 
from hardware,incidents 
where hardware.id = incidents.hardware_id and incidents.resolved=0;

像这样的东西应该可以做到:

Select A.HardwareID A.HadwareName, B.UnresolvedCount
From (Hardware A) 
Inner Join 
(
  Select HardwareID, Count(1) As UnresolvedCount 
  From Incidents 
  Where Resolved = 0 
  Group By HardwareID
) As B On A.HardwareID = B.HardwareID

这也可以奏效

SELECT hd.name, inc.issue, FROM hardware hd INNER JOIN inc ON hd.tag = inc.tag AND inc.issue = 'unresolved' group by hd.name