PHP Check if string is in table - php

Question

So i've been trying to sort this issue out for a while but been unable to figure out if i have to do this trough SQL side or the PHP side.
My code i have so far:
<?php
$servername="";
$username = "";
$password = "";
$dbname = "alphacre_kingsland";
$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
$sql = "SELECT * FROM `bm_player_bans` ORDER BY id";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result)>0){
while($row = mysqli_fetch_assoc($result)){
$playerId = bin2hex($row['player_id']);
$storedname= getPlayerName($playerId);
$sql = "INSERT INTO bm_onlinedata (uuid, playername) VALUES ('".$playerId."', '".$storedname."')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
}
}else{
echo "0 results";
}
mysqli_close($conn);
function getPlayerName($uuid){
$json_response = file_get_contents("https://sessionserver.mojang.com/session/minecraft/profile/".$uuid);
$data = json_decode($json_response);
return $data->name;
}
?>
So this stores "UUID" and playername into a seperate table. But i want to check if the UUID is already in there before it adds a new one. Basicly updating it.
This is because playernames can change. And i don't want multiple rows of the same data.
But thats ONLY if its there ofc.
Background information:
I'm fetching the username from a user trough Mojangs API, wich only allows a single lookup of that UUID every minute. So i want to get the data every 5 minutes or so using a scheduled task running this script and store it in a table.

Answer 1

You can easily check with select
$sql = "SELECT * FROM `bm_player_bans` ORDER BY id";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result)>0){
while($row = mysqli_fetch_assoc($result)){
$playerId = bin2hex($row['player_id']);
$storedname= getPlayerName($playerId);
$sql = "SELECT * FROM `bm_onlinedata` where uuid = '" . $playerId ."';";
$result = mysqli_query($link, $sql);
$num_rows = mysqli_num_rows($result);
if ($num_rows> 0) {
$sql = "UPDATE bm_onlinedata
set playername = '". $storedname."'
where uuid = '" .$playerId ."';"; )";
} else {
$sql = "INSERT INTO bm_onlinedata (uuid, playername) VALUES ('".$playerId."', '".$storedname."')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
}
}
}else{
echo "0 results";
}