MySQL GROUP BY return the first item - Need to select the last item

I have a table that has duplicate data for the same user_id. I need to select the newest record for each user_id. When i use group by then order. mysql does the function in that order and i get the wrong records.

Table - tblUsersProfile

Field Type 开发者_C百科Null Default Comments id int(11) No AI

user_id int(7) No

first_name_id int(11) No

last_name_id int(11) No

location_id int(11) No

dob date Yes NULL

sex int(1) Yes NULL 1 for Male, 0 for Female created_by int(21) No

activity_ts timestamp No CURRENT_TIMESTAMP

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select t1.* from tblUsersProfile as t1
inner join (
select user_id,max(activity_ts) as rct
from tblUsersProfile
group by user_id) as t2
on t1.user_id = t2.user_id and t1.activity_ts = t2.rct

Maybe my query is even more "complicated" than necessary if you have all the others data redundants and equals for all records.