php - Mysql Getting last entry in Group By -

hey mysql query

$userid="id of logged in user"; 

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select id, max( post_time ) , message, user_name, receiver_id, sender_id chat receiver_id =$userid or sender_id =$userid group greatest( receiver_id, sender_id ) , least( receiver_id, sender_id )  order id desc  limit 0 , 1000 

it gives first message recorded between 2 user not last. want last message show in message inbox. use query show unique conversations in inbox different users of logged in user(or u can particular user) can check demo @ http://www.funnenjoy.com/home

try this,

select id, message, user_name, receiver_id, sender_id chat post_time = max(post_time) , (receiver_id =$userid or sender_id =$userid) group greatest( receiver_id, sender_id ) , least( receiver_id, sender_id )  order id desc  limit 0 , 1000