Excluding row in database with != in PDO query - php

Question

I'm trying to exclude certain rows with a PDO query but it is not returning the right value and I'm not seeing my error maybe some of you can help me.
This is the first query that works.
$objGetRecievedChat = $objDatabaseMessages->prepare('SELECT * FROM messages WHERE recieverid = :recieverid GROUP BY chatid');
Now I want to exclude the chatid's that I get from this query.
foreach ($getRecievedChatFtch as $chatid) {
echo $chatid['chatid'] . '<BR>';
}
When I echo the above I get the next result:
20920
81586
Wich is correct I want to exclude those two values so I execute the next query:
$objGetSendChat = $objDatabaseMessages->prepare('SELECT * FROM messages WHERE ownerid = :ownerid AND chatid != :chatid GROUP BY chatid');
foreach ($getSendChat as $key ) {
echo $key['chatid'] . '<BR>';
}
But when I echo the above I get the next values
44495
20920
44495
this value 44495 is correct although I only need it once (that is why I GROUP BY chatid) But the value 20920 is one of the values I need to exclude.
Does anyone know what I'm doing wrong?
Thanks in advance!
Whole code:
//Voor de berichten die je hebt ontvangen.
$objGetRecievedChat = $objDatabaseMessages->prepare('SELECT * FROM messages WHERE recieverid = :recieverid GROUP BY chatid');
$objGetRecievedChat->bindParam('recieverid', $member_id);
$objGetRecievedChat->execute();
$getRecievedChatFtch = $objGetRecievedChat->fetchAll(PDO::FETCH_ASSOC);
//Dit is voor verzonden berichten.
foreach ($getRecievedChatFtch as $chatid) {
echo $chatid['chatid'] . '<BR>';
$objGetSendChat = $objDatabaseMessages->prepare('SELECT * FROM messages WHERE ownerid = :ownerid AND chatid NOT IN(:chatid) GROUP BY chatid');
$objGetSendChat->bindParam('ownerid', $member_id);
$objGetSendChat->bindParam('chatid', $chatid['chatid']);
$objGetSendChat->execute();
$getSendChat = $objGetSendChat->fetchAll(PDO::FETCH_ASSOC);
foreach ($getSendChat as $key) {
echo $key['chatid'] . '<BR>';
}
}

Answer 1

Change query to catid NOT IN (xxxx,xxxx).

Answer 2

You're making it wrong: in your foreach loop, you retrieve ALL rows BUT the current one. You must put the query out of the foreach and use a WHERE IN
//Voor de berichten die je hebt ontvangen.
$objGetRecievedChat = $objDatabaseMessages->prepare('SELECT * FROM messages WHERE recieverid = :recieverid GROUP BY chatid');
$objGetRecievedChat->bindParam('recieverid', $member_id);
$objGetRecievedChat->execute();
$getRecievedChatFtch = $objGetRecievedChat->fetchAll(PDO::FETCH_ASSOC);
//Dit is voor verzonden berichten.
$chatids = array();
foreach ($getRecievedChatFtch as $chatid) {
echo $chatid['chatid'] . '<BR>';
$chatids = $chatid['chatid'];
}
$placeholders = implode(',', array_fill('?', count($chatids)));
$objGetSendChat = $objDatabaseMessages->prepare('SELECT * FROM messages WHERE ownerid = ? AND chatid NOT IN(' . $placeholders . ') GROUP BY chatid');
$objGetSendChat->execute(array_merge(array($ownerid, $chatids)));
$getSendChat = $objGetSendChat->fetchAll(PDO::FETCH_ASSOC);
foreach ($getSendChat as $key) {
echo $key['chatid'] . '<BR>';
}
More or less (because I dislike using WHERE IN with prepared statement. You usually can avoid them with JOIN.
$objGetSendChat = ...
While you use $getSendChat in the foreach.
So I feel we're missing some code here, that contains the error.
Plus, you do a GROUP BY chatid and you get 44495 twice in the result, so the result cannot be the query's one.