Multiple inner joins in MySql not working - php

Question

I have 3 tables :
useractivitylog
id userid activity_type activity_id date
which will store all user activities.
requestfriend
opid userid friendid requesttime message source requesttype friendemail status
which will store friends details. userid and friendid can be the user's id. If user A has send friend's request to user B, then userid will contain the id of A and friendid will be the id of B. So anyway B is the friend of A and A is the friend of B.
auth_user_profiles
id user_id first_name last_name profileimage
which stores user profile information.
What I need is to select all my friends activities from useractivitylog table. I tried with the following query. But it didnt worked.
echo "select ua.*,rf.opid,aup.user_id,aup.first_name,aup.last_name,
aup.profileimage from useractivitylog as ua INNER JOIN requestfriend as rf
INNER JOIN auth_user_profiles as aup on
aup.user_id= IF (rf.userid='$userid',rf.friendid,rf.userid)
WHERE (rf.userid=$userid or rf.friendid=$userid)
and rf.status='2' and ua.userid!=$userid";
Here, $userid is my user id. Actually what I want is to retrieve the profile information and the activities of users who are friends of mine. But know, it is returning all rows in useractivitylog table even if the userid is not in my friends list.
Can anyone help me to find an appropriate query for this. Thanks in advance.

Answer 1

You don't join properly. The only condition for a useractivitylog being linked to the other tables is that its user ID is not $userid. That is true for most records in the table, so you almost get a cartesian product (cross join).
BTW: You don't join auth_user_profiles properly either, because you compare with the string '$userid' instead of comparing with $userid.
Let's re-write the statement such that we retrieve the friends first and join the other tables with these:
select
ua.*,
friend.opid,
aup.user_id,
aup.first_name,
aup.last_name,
aup.profileimage
from
(
select distinct
case when userid = $userid then friendid else userid end as id,
opid
from requestfriend
where $userid in (userid, friendid) and status = '2'
) as friend
inner join useractivitylog as ua on ua.userid = friend.id
inner join auth_user_profiles as aup on aup.user_id = friend.id;

Answer 2

This should work as you explained you need to get the activities of users who are friends with you, you first need to join useractivitylog table to requestfriend where friendid is in useractivitylog i.e ON(rf.friendid =ua.userid) then you need to join auth_user_profiles table where userid from useractivitylog table is equal,i.e ON(ua.userid=aup.user_id) and then use you where filter on rf.userid is equal to the provided user id ,i didn't get the point of using OR rf.friendid = $userid comparison when you asked for the friends activity then why comparing friend's id to the given user id
SELECT
ua.*,
rf.opid,
aup.user_id AS aup_user_id,
aup.first_name,
aup.last_name,
aup.profileimage
FROM
useractivitylog AS ua
INNER JOIN requestfriend AS rf ON(rf.friendid =ua.userid)
INNER JOIN auth_user_profiles AS aup ON(ua.userid=aup.user_id)
WHERE
rf.userid = $userid
AND rf.status = '2'
Using a sub select
SELECT
ua.*,
aup.user_id AS aup_user_id,
aup.first_name,
aup.last_name,
aup.profileimage
FROM
useractivitylog AS ua
INNER JOIN auth_user_profiles AS aup ON(ua.userid=aup.user_id)
WHERE
ua.userid IN (
SELECT friendid FROM requestfriend WHERE userid =$userid AND `status` = '2'
)

Answer 3

Try as below query
select * from useractivitylog a,requestfriend b,auth_user_profiles c
WHERE a.userid = b.userid and b.userid = c.userid;

Answer 4

You could go from the other side to your data...
Start with selecting all your friends and if you have them, get their data:
SELECT
ua.*,
rf.opid,
aup.user_id,
aup.first_name,
aup.last_name,
aup.profileimage
FROM
requestfriend AS rf
JOIN
useractivitylog AS ua ON (ua.userid = rf.friendid)
JOIN
auth_user_profiles AS uap ON (uap.userid = rf.friendid)
WHERE rf.userid = $userid AND rf.status = '2'
The rest with the vice-versa connection in your requestfriend table should be no problem.
Since the friendrequests should be not as much as the activities, this might lead to better performance in case you have loads of data...

Answer 5

You need to add a field to JOIN your first table on:
SELECT ua.*, rf.opid, aup.user_id, aup.first_name, aup.last_name, aup.profileimage
FROM useractivitylog as ua
INNER JOIN requestfriend as rf on fieldname = fieldname
INNER JOIN auth_user_profiles as aup on aup.user_id = IF (rf.userid='$userid',rf.friendid,rf.userid)
WHERE (rf.userid=$userid or rf.friendid=$userid)
AND rf.status='2'
AND ua.userid!=$userid