Sometimes we need to specify the file charset before writing the data to a file. The data strings which we get from the database are in UTF-8 so we have to convert them in proper charset. This could be done be iconv().
For example, i want to write the Traditional Chinese in Big5. The conversion could be done by.
$big5_str = iconv('UTF-8', 'Big5', $utf8_str);
Reference: StackOverflow – PHP – UTF-8 to Chinese ANSI (GB2312?) – Export CSV file