只有最后一个查询返回MySQL的结果

Question

I am querying a MySQL database through PHP. I read input from a file. Then loop over the inputs to query the database to retrieve 3 attributes for each input.

The database connection is fine. All the queries run fine otherwise. What is happening is for all the queries but the last one I get mysql_num_rows($result) = 0. And only for the last one it prints correct results.

I cannot figure out why. What might possibly be wrong?

$fh = fopen($my_File, 'r');
$arr = explode("
", fread($fh, filesize($my_File)));
fclose($fh);
foreach ($arr as $line) {     
    if ($line != "
" || $line != "" || $line != NULL) {
    $query = "SELECT id, name, status FROM table1 WHERE id='$line'";   
    $result = mysql_query($query);
    if (!$result) {
        die('Invalid query: ' . mysql_error());
    }
    $num = mysql_num_rows($result);
    if ($num == 0) {
       echo "NULL Set<br/>";       
    } else {
       echo "RESULT Set<br/>";
    }
}

Answer 1

Is it possible that the lines in your file are terminated by " " rather than just " "? If so, you'll have an extra "" at the end of each element of $arr (except the last).

Try adding

$line = trim($line);

at the beginning of your foreach loop and see if it makes a difference.

Better yet, use fgets instead of fread.