Question

I use some code here, transfer mysql query data into json data and write into a file. where is the problem? why the file is zero kb?

while($row = mysql_fetch_array($Query)){ 
  $arr = array ('name'=>$row['name']);
  $jsondata = json_encode($arr);
  $countfile="data.txt";
  if(!file_exists($countfile))
  {
    fopen($countfile,"w");
  } 
  $fp = fopen($countfile, 'r');
  fwrite($fp, $jsondata);
  fclose($fp);
}

Answer 1

Because you’re reopening the file as read only

$fp = fopen($countfile, 'r');

try

$fp = fopen($countfile, 'w'); // to write

or

$fp = fopen($countfile, 'a'); // to append

you could also open the file for writing at the start, append your rows in a variable and then write it all together to the file.

$countfile="data.txt";
$fp = fopen($countfile, 'w');
while($row = mysql_fetch_array($Query))
{ 
    $arr = array ('name'=>$row['name']);
    $jsondata .= json_encode($arr) . "\n";

}
fwrite($fp, $jsondata);
fclose($fp);