Write a file with encoding UTF-8 in php

I do not know of a database that will do the encoding conversion for you easily. For example, in MySQL, you have to reset all the character encodings for the db, tables, and columns, AND THEN convert the data.

I would suggest instead that you create your database dump and use iconv to change the encoding, whether on the command line:

iconv -f original_charset -t utf-8 dumpTextData > convertedTextData

or in PHP (taken from How to write file in UTF-8 format?)

$input = fopen($file, 'r');
$output = fopen($file, 'w');
stream_filter_append($input, 'convert.iconv.UTF-8/OLD-ENCODING');
stream_copy_to_stream($input, $output);
fclose($input);
fclose($output);

NOTE: edited to avoid leaking file descriptors.

Excel likes CSV files to be UTF-16LE, and begin with '\xFF\xFE'.

My code to build a file for excel is:

echo "\xFF\xFE"; // marker for UTF-16 file;

foreach ($rows as $row)
    echo mb_convert_encoding($row, 'UTF-16LE');

Old encoding is first, as it is in iconv function. You also can´t read and write same file.

    $input = fopen($path, 'r');
    $output = fopen($path . '.tmp', 'w');
    stream_filter_append($input, 'convert.iconv.OLDENCODING/UTF-8');
    stream_copy_to_stream($input, $output);
    fclose($input);
    fclose($output);
    unlink($path);
    rename($path . '.tmp', $path);