U are trying to export it using phpmyadmin?
I sugested to make a script that extract all the values from your field and create de csv files.
$csv_content = "";
$sql_txt = "SELECT emails FROM table";
$sql_rez = mysql_query($sql_txt) or die(mysql_error());
while ($sc = mysql_fetch_assoc($sql_rez)) {
$csv_content.= "{$sc['emails']}\r\n";
}mysql_free_result($sql_rez);
$csv_file_name = "my_file.csv";
if (($handle = fopen($csv_file_name,"w"))) {
if (fwrite($handle, $csv_content) === FALSE) {
echo "Cannot write to file ($csv_file_name)";
exit;
} else {
echo "File ($csv_file_name) successfully create!!!";
}
}
fclose($handle);
Something like that ...