<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$mysqli->query("SELECT 42/0");

if ($mysqli->warning_count > 0) {
    $result = $mysqli->query("SHOW WARNINGS");
    $row = $result->fetch_row();
    printf("%s (%d): %s\n", $row[0], $row[1], $row[2]);
}

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

mysqli_query($link, "SELECT 42/0");

if (mysqli_warning_count($link) > 0) {
    $result = mysqli_query($link, "SHOW WARNINGS");
    $row = mysqli_fetch_row($result);
    printf("%s (%d): %s\n", $row[0], $row[1], $row[2]);
}