Enable the class LocalGroupMembers from here > http://praveenkumarsharma1.blogspot.com/2014/10/enable-members-of-all-local-groups-of.html

SQL Query to find domain users who are administrators on the workstations/servers

SELECT v_R_System.Netbios_Name0, v_R_System.User_Name0, v_R_System.AD_Site_Name0, LocalGroupMembers_DATA.Account00, LocalGroupMembers_DATA.Category00, LocalGroupMembers_DATA.Disabled00, LocalGroupMembers_DATA.Domain00, LocalGroupMembers_DATA.Name00,
LocalGroupMembers_DATA.Type00
FROM LocalGroupMembers_DATA INNER JOIN
v_R_System ON LocalGroupMembers_DATA.MachineID = v_R_System.ResourceID
where Name00 like ‘%Administrators%’ and Type00 like ‘%Domain%’ and Category00 like ‘%UserAccount%’

Output :