ios - Is it possible to query PFSessions to see when users were 'last active? -

i have admin view lists of parse users , can't seem figure out how query parse's new sessions class. i'm trying show label says "last seen at: ____ " , fill in blank date. users on running up-to-date session tokens (i created database after parse did switch over, no migration necessary).

with code below, error:

"[error]: no results matched query (code: 101, version: 1.7.1)" nslog: last seen at: (null)

pfquery *sessionquery = [pfsession query]; [sessionquery wherekey:@"user" equalto:clientuserobject]; [sessionquery getfirstobjectinbackgroundwithblock:^(pfobject *session, nserror *error){          nsdate *lastseen = session.updatedat;         nsdateformatter *dateformatter = [[nsdateformatter alloc] init];         [dateformatter setdatestyle:nsdateformattermediumstyle];         [dateformatter settimestyle:nsdateformattermediumstyle];         nsstring *formatteddatestring = [dateformatter stringfromdate:lastseen];          cell.lastseenlabel.text = formatteddatestring;         nslog(@"last seen at: %@", formatteddatestring)     }]; 

you're not able query "last seen" pfsession table. entries of table automatically removed if user logs out. you're able find logged in users.

if want "last seen" property, should save in pfuser table when log out . add column.

hope helps.