PHP trim not working - php

Question

I m trying to get rid of the trailing comma my sql statemen using trim but it doesnt seem to work
if(isset($_POST['report'])){
//====
$sql = 'INSERT INTO weekly_repo ( hospnme, disease, week, under5, above5, dat) VALUES ';
$week = intval($_POST['current_week']);
$diseases = $_POST['diseases'];
foreach($diseases as $disease){
$sql .= ' ( "' . filterString($_POST['hospital']). '", "' . filterString($disease['disease']) . '", ' . $week . ', ' . intval($disease['under_5']) . ', ' . intval($disease['over_5']) . ', NOW()), ';
}
$sql = trim($sql, '\,');
// ended up doing this
//$sql = substr($sql, 0, strrpos($sql, ',')) . ';';
$stmt = $conn->query($sql);
}

Answer 1

You don't need to escape \ the comma. A better approach might be to construct an array and then implode():
foreach($diseases as $disease){
$sql[] = ' ( "' . filterString($_POST['hospital']). '", "' . filterString($disease['disease']) . '", ' . $week . ', ' . intval($disease['under_5']) . ', ' . intval($disease['over_5']) . ', NOW()), ';
}
$sql = implode(',', $sql);