PHP mysqli_errno() 函数

<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

// Perform a query, check for error
if (!mysqli_query($con,"INSERT INTO Persons (FirstName) VALUES ('Glenn')"))
{
echo("Errorcode: " . mysqli_errno($con));
}

mysqli_close($con);
?>