Delete by AJAX request - php

Question

I have a button which call this AJAX request to delete record.
How could I show/handle mysql errors correctly like:
Error: Table 'supplier_contacts' doesn't exist
// DELETE
$('.delete-btn').click(function () {
// Confirm
if (!confirm('Are you sure want to delete this row?')) {
return false;
}
// id need to delete
var contact_id = $(this).attr('contact_id');
// Current button
var obj = this;
// Delete by ajax request
$.ajax({
type: "post",
dataType: "text",
url: 'suppliers_sql.inc.php?a=delete_contact',
data: {
contact_id: contact_id
},
success: function (result) {
$(obj).parent().parent().remove();
window.location.assign('suppliers_details.php?id=<? echo $supplier_id ?>&m=success');
}
});
});
SQL QUERY of suppliers_sql.inc.php ? a = delete_contact
// --------------------------------------------------------------------------------------------
// DELETE CONTACT
// --------------------------------------------------------------------------------------------
if ($_REQUEST['a'] == "delete_contact") {
$contact_id = $_POST['contact_id'];
$sql_contact = "DELETE FROM supplier_contacts WHERE contact_id = $contact_id";
if (mysqli_query($mysqli, $sql_contact)) {
mysqli_close($mysqli);
//header("Location: suppliers_details.php?id=$supplier_id&m=success");
exit;
} else {
echo "Error: " .$sql_contact. "<br>" .mysqli_error($mysqli);
mysqli_close($mysqli);
exit;
}
}

Answer 1

As you are echoing something if there is an error you can display it in your success.
$.ajax({
type : "post",
dataType : "text",
url : 'suppliers_sql.inc.php?a=delete_contact',
data : {
contact_id : contact_id
},
success : function(result){
if(result)
{
//Your error
alert(result);
}
else
{
//all good
$(obj).parent().parent().remove();
window.location.assign('suppliers_details.php?id=<? echo $supplier_id ?>&m=success');
}
}
});