How can I use mysqli_fetch_array() twice?

I am using the entries from a database to fill a row and a column in a table. But I cannot access the SQL returned data twice using mysqli_fetch_array() twice. I need to loop mysqli result more than once. This doesn’t work:

//Copy the result
$db_res = mysqli_query( $db_link, $sql );
$db_res2=$db_res;

//Top row
while ($row = mysqli_fetch_array( $db_res, MYSQL_ASSOC))
{
        echo "<td>". $row['Title'] . "</td>";
}

//leftmost column
while ($row = mysqli_fetch_array( $db_res2, MYSQL_ASSOC))
{
                    echo "<tr>";
        echo "<td>". $row['Title'] . "</td>";
                    .....
                    echo "</tr>";
}

How can I apply mysqli_fetch_array twice on the same result?

Answer

You don’t need the while loop and you don’t need to use mysqli_fetch_array() at all!

You can simply loop on the mysqli_result object itself many times. It implements Traversable interface that allows it to be used in foreach.

//Top row
foreach($db_res as $row) {
    echo "<td>". $row['Title'] . "</td>";
}

//leftmost column
foreach($db_res as $row) {
    echo "<tr>";
    echo "<td>". $row['Title'] . "</td>";
    .....
    echo "</tr>";
}

However, you should separate your DB logic from your display logic and to achieve this it is best to use fetch_all(MYSQLI_ASSOC) in your DB logic to retrieve all records into an array.

If you fetch all the data into an array, you can loop that array as many times as you want.

$data = $db_res->fetch_all(MYSQLI_ASSOC);

foreach($data as $row) {
    // logic here...
}