PHP while loop iterates only once

Question

Quick Question;

$sql = mysql_query("SELECT * FROM cronjobs WHERE status = 0 ");

while($cronjob = mysql_fetch_array($sql)){
    if($cronjob['suid'] != $cronjob['cuid']){
        //echo 'not equal<br>';
        $set = 0;
        $sid = $cronjob['sid'];
        $suid = $cronjob['suid'];
        $cuid = $cronjob['cuid'];
        $set = notify($sid, $suid, $cuid);
        if($set==1){
            //echo 'notified<br>';
            $sql = "UPDATE cronjobs SET status = '1' WHERE id='".$cronjob['id']."'";
            if(mysql_query($sql)){
               echo '1<br>';
              $set = 0;
          }
        }
      }
   }
}

notify() will return 1 (numeric)

The problem is only one iteration of the while loop is executed even though there are more records. I don't know what's wrong here. Help me out pls.

Is your if condition inside while loop true for multiple records? — heyanshukla
– heyanshukla, Commented May 22, 2012 at 10:53
@heyanshukla could be. but majority of the records wouldn't be. this just stops after processing one record. — Prabhakar Siddhant
– Prabhakar Siddhant, Commented May 22, 2012 at 10:57
then first of all echo somethihng out of if condition in while loop.and check the number of iteration. — heyanshukla
– heyanshukla, Commented May 22, 2012 at 10:59

Ganesh Bora · Accepted Answer · 2012-05-22 11:02:15Z

5

Please change inner $sql variable name to something else..outer $sql and inner one are making conflict

$sql = mysql_query("SELECT * FROM cronjobs WHERE status = 0 ");

while($cronjob = mysql_fetch_array($sql)){
    if($cronjob['suid'] != $cronjob['cuid']){
        //echo 'not equal<br>';
        $set = 0;
        $sid = $cronjob['sid'];
        $suid = $cronjob['suid'];
        $cuid = $cronjob['cuid'];
        $set = notify($sid, $suid, $cuid);
        if($set==1){
            //echo 'notified<br>';
            $sql_2 = "UPDATE cronjobs SET status = '1' WHERE id='".$cronjob['id']."'";
            if(mysql_query($sql_2)){
               echo '1<br>';
              $set = 0;
          }
        }
      }
   }
}

answered May 22, 2012 at 11:02

Ganesh Bora

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Comments

Gautam Sharma · Accepted Answer · 2012-05-22 11:21:50Z

1

Just an observation:

Because you have:

$sql = mysql_query("SELECT * FROM cronjobs WHERE status = 0 ");  
while($cronjob = mysql_fetch_array($sql)){

Its going to execute the Query EVERY SINGLE time it goes through the loop. If you have a 100 rows, its going to execute 100 times. If you do this instead, then it executes only once.

$sql = mysql_query("SELECT * FROM cronjobs WHERE status = 0 ");  
$res = mysql_fetch_array($sql);
while($cronjob = $res){

It wouldnt have conflicted either!

answered May 22, 2012 at 11:21

Gautam Sharma

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1 Comment

Gautam Sharma Over a year ago

Its certainly not passed by ref, sir.

Kashif · Accepted Answer · 2019-06-23 12:19:38Z

0

It is clearly an issue that occurs when you have the same variable for query ($query) and Result Object ($result).try different name for mysql_query() inside the WHILE Loop.

answered Jun 23, 2019 at 12:19

Kashif

382 bronze badges

1 Comment

Dharman Over a year ago

This is the same recommendation as the accepted answer.

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