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Select and then select individual values ​​again

I have 3 columns questionid, replyidand userid.

I want to select everything questionid from userid where userid is session[userid], and then select from it questionid.

Right now, I take all those questionidbelonging $_SESSION['user_id']to the array (and delete duplicates from it), and then I pass another request again

foreach($array as $x)
{
$query="select questionid,replyid,userid from table where questionid=$x"
}

But I think the above steps can be performed in the request itself ( and the above step also does not work ). I tried below but did not work. If I try to pass this request, then a duplicate value will be added:

SELECT distinct(questionid),replyid,userid 
from table 
where userid=$_SESSION['user_id']

So what should be the request?

questionid,replyid,userid

8          ,2     ,45

8          ,3      ,45

9           ,8      ,41

8,2 8,3 - ( ), ...

, , questionid, * from table where questionid .

, ,

 SELECT distinct questionid, `answerid`, `userid`
 FROM `table` 
 WHERE  userid='$user'

. limit 0,1

 SELECT distinct questionid, `answerid`, `userid`
 FROM `table`
 WHERE  userid='$user' 
 LIMIT 0,1
+5
1

, :

SELECT DISTINCT questionid, replyid, userid 
FROM table 
WHERE questionid IN
(
    SELECT DISTINCT questionid
    FROM table 
    WHERE userid = @user_id
)

DISTINCT questionid, replyid, userid. , DISTINCT(questionid).

distinct questionid, GROUP BY questionid replyid, userid, SUM, MAX MIN.

+1

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