PHP mysqli_fetch_lengths() 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();
}

$sql="SELECT * FROM Persons ORDER BY Lastname";

if ($result=mysqli_query($con,$sql))
{
$row=mysqli_fetch_row($result);

// Display field lengths
foreach (mysqli_fetch_lengths($result) as $i=>$val)
{
printf("Field %2d has length: %2dn",$i+1,$val);
}

// Free result set
mysqli_free_result($result);
}

mysqli_close($con);
?>