Select the last inserted row Every 1 second - php

Question

I have 2 files:
1. chat.php: contain chat messages.
2. loadSingle.php: grab last new message every 1 second.
When I get the last message it was always return and get the last one. I want to get the last message without duplicate every time.
chat.php:
function loadlastmsg(){
var fromIdl = "<?php echo $chat_from_id;?>";
$.ajax({
type:'POST',
url:'loadSingle.php',
data:{fromIdl: fromIdl,},
cache: false,
beforeSend:function(data){
},
success: function(data)
{
$('#mainmsgs').append(data);
}
});
}
setInterval(function(){
loadlastmsg();
}, 1000);
</script>
Load Last Message
loadSingle.php:
<?php
if(isset($_POST["fromIdl"], $_POST["fromIdl"]))
{
$chat_from_ids = $_POST["fromIdl"];
require_once 'config/config.php';
mysqli_set_charset($conn,"utf8mb4");
$chinbox = array();
$result=$conn->query("SELECT * FROM chat WHERE id = (SELECT MAX(id) FROM chat WHERE to_id=$userId AND from_id=$chat_from_ids OR to_id=$chat_from_ids AND from_id=$userId) ORDER BY chat.send_date DESC LIMIT 1");
while ($chinbxsx = mysqli_fetch_assoc($result)) {
$chinbox[] = $chinbxsx;
$from_id = $chinbxsx['from_id'];
$subject = $chinbxsx['subject'];
$message = $chinbxsx['message'];
$get_date = $chinbxsx['send_date'];
$senddate = date_create($chinbxsx['send_date']);
$senddate = date_format($senddate, 'Y/m/d H:i:s');
$from_name = $chinbxsx['from_name'];
if($from_id != $userId){
$from_image = $chinbxsx['from_image'];
$msgclass = 'msgmRec';
}else{
$from_image = $userImage;
$msgclass = 'msgmSend';
}
// if($get_date > $get_date){
echo "<div class='msgm $msgclass'><img class='cmavsm' id='cmavsm' style='background-image: url($from_image);' /><p class='smRec'>$message</p><span class='date_span'>$senddate</span></div>";
// }
}
$conn->close();
}
?>
The mistake is: get the last message every 1 second. every time without stop it. I want to get the last message one time without loop the last message. thanks.

Answer 1

Using Ajax for chat will have poor performance always. You must consider using Web sockets.
See the below link for a sample
https://phppot.com/php/simple-php-chat-using-websocket/

Answer 2

I can't warranty this will be a fixed code, but it will give you the idea of how to discard a message on the client side if already received:
CLIENT SIDE:
<script>
/* Other code ... */
// Global variable for save the latest message ID.
var _latestMessageID = -1;
$(document).ready(function()
{
// Start getting messages...
setInterval(
function() {loadlastmsg();},
1000
);
});
function loadlastmsg()
{
var fromIdl = "<?php echo $chat_from_id;?>";
var formData = {fromIdl: fromIdl};
$.ajax({
type:'POST',
url:'loadSingle.php',
data: $.param(formData),
cache: false,
success: function(data)
{
if (data && data["ID"] > _latestMessageID)
{
$('#mainmsgs').append(data["message"]);
_latestMessageID = data["ID"];
}
}
});
}
</script>
SERVER SIDE:
<?php
require_once 'config/config.php';
if(isset($_POST["fromIdl"]) && $_POST["fromIdl"])
{
$chat_from_ids = $_POST["fromIdl"];
mysqli_set_charset($conn,"utf8mb4");
$chinbox = array();
$result=$conn->query(
"SELECT *
FROM chat
WHERE id = (SELECT MAX(id)
FROM chat
WHERE (to_id=$userId AND from_id=$chat_from_ids)
OR (to_id=$chat_from_ids AND from_id=$userId))
ORDER BY chat.send_date DESC LIMIT 1"
);
// Since the query has LIMIT of 1 this should only loop one time.
while ($chinbxsx = mysqli_fetch_assoc($result))
{
$chinbox[] = $chinbxsx;
$from_id = $chinbxsx['from_id'];
$subject = $chinbxsx['subject'];
$message = $chinbxsx['message'];
$get_date = $chinbxsx['send_date'];
$senddate = date_create($chinbxsx['send_date']);
$senddate = date_format($senddate, 'Y/m/d H:i:s');
$from_name = $chinbxsx['from_name'];
if ($from_id != $userId)
{
$from_image = $chinbxsx['from_image'];
$msgclass = 'msgmRec';
}
else
{
$from_image = $userImage;
$msgclass = 'msgmSend';
}
$msgID = $chinbxsx['id'];
}
$returnArray = array();
$returnArray["ID"] = $msgID;
$returnArray["message"] = "<div class='msgm $msgclass'><img class='cmavsm' id='cmavsm' style='background-image: url($from_image);' /><p class='smRec'>$message</p><span class='date_span'>$senddate</span></div>";
echo json_encode($result);
$conn->close();
}
?>