Saving SQL Server query data to a CSV file (query from GET/POST request)

csv.php

<?php

/**
 * Connect to SQL server (SQLSRV can also be used, I used MSSQL because Native Client isn't needed)
 * Replace <server>, <username>, and <password> with the appropriate details
 */
$link = mssql_connect("<server>", '<username>', '<password>');

if (!$link)
{
    die('Something went wrong while connecting to MSSQL');
}

// I used a GET query for debugging (to access with URL), but POST probably works better in production
if (isset($_GET["q"])) :
    
    $query = mssql_query($_GET["q"]);
    $fields = mssql_num_fields ( $query );
    $header = "";
    $data = "";
    
    for ( $i = 0; $i < $fields; $i++ )
    {
        $header .= mssql_field_name( $query , $i ) . ",";
    }
    
    while( $row = mssql_fetch_row( $query ) )
    {
        $line = '';
        foreach( $row as $value )
        {
            if ( ( !isset( $value ) ) || ( $value == "" ) )
            {
                $value = ",";
            }
            else
            {
                $value = str_replace( '"' , '""' , $value );
                $value = '"' . $value . '"' . ",";
            }
            $line .= $value;
        }
        $data .= trim( $line ) . "\n";
    }
    $data = str_replace( "\r" , "" , $data );
    
    if ( $data == "" )
    {
        $data = "\n(0) Records Found!\n";
    }
    
    header("Content-type: text/csv");
    header("Content-Disposition: attachment; filename=data.csv");
    header("Pragma: no-cache");
    header("Expires: 0");
    print "$header\n$data";

else :

    echo "SQL query not defined.";

endif;

?>