PHP while loop returning null result

Question

$connect_status = "SELECT connected_to_id FROM tbl_connect WHERE user_id = 
{$_SESSION['user_id']}";

$exec_connstatus_query = mysql_query($connect_status, $db_connect);

while($check_status = mysql_fetch_array($exec_connstatus_query))
{   
  if ($check_status['connected_to_id'] == $profileid)
  {
    echo "{$check_status['connected_to_id']}";
  }
  else
  {
    echo "fail";
  }
}

This code has been troubling me for 3 hours. Here the issue is even if this condition:

if ($check_status['connected_to_id'] == $profileid)

returns false, I am not able to see "fail" when the else statement executes. Any ideas?

What kind of values can be in that connected_to_id field, and what's the value in $profileid? PHP will consider many comparison to be TRUE, even though any reasonable person wouldn't, e.g. the field in the database is NULL, and $profileid is 0 or an empty string. — Marc B
– Marc B, Commented Jun 15, 2012 at 15:48
Is this all your code? if you echo $check_status['connected_to_id'] and $profileid, what do they show? Should there be another '}' to close the while loop, or is it just missed in the question. — phenomnomnominal
– phenomnomnominal, Commented Jun 15, 2012 at 15:48
Is the first line with {} a valid php syntax? Can someone confirm? — Subir Kumar Sao
– Subir Kumar Sao, Commented Jun 15, 2012 at 15:49
@subirkumarsao: yes, it's valid. it's PHP syntax for embedding "complex" vars into double-quoted strings. e.g. $x ="$arr[a][b]" would normally fail because PHP's parser isn't gready and would only treat $arr[a] as an array, followed by a couple brackets and a b. using {} around the whole thing forces php to treat both bracket bits as part of the array dereference. — Marc B
– Marc B, Commented Jun 15, 2012 at 15:50

TerryE · Accepted Answer · 2012-06-15 16:07:12Z

1

mysql_query() returns FALSE on error and the loop won't execute at all. This would occur if $_SESSION['user_id'] is not numeric. why not just

$connect_status = "SELECT connected_to_id FROM tbl_connect WHERE user_id ='$_SESSION[user_id]'";

Ditto mysql_fetch_array() returns FALSE if there are no (more) rows. If your session doesn't exist in tbl_connect then the loop won't execute. Don't you want something like:

$connect_status = "SELECT connected_to_id FROM tbl_connect 
                   WHERE user_id ='$_SESSION[user_id]' LIMIT 1";
$exec_connstatus_query = mysql_query($connect_status, $db_connect);
if( ($check_status = mysql_fetch_array($exec_connstatus_query)) && 
    ($check_status['connected_to_id'] == $profileid) ) {
    echo "{$check_status['connected_to_id']}";
} else {
    echo "fail";
}

edited Jun 15, 2012 at 16:07

answered Jun 15, 2012 at 15:53

TerryE

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1 Comment

TerryE Over a year ago

my Q status now is "edited edited 53 mins ago"answered 1 hour ago" Yr comment was timestamped an hr ago => you made a comment so I updated my answer accordingly.

Nishu Tayal · Accepted Answer · 2012-06-15 15:51:36Z

0

I would suggest you to check $exec_connstatus_query first, because it may be that your query is not executed properly and thats why control did not go inside while loop. And your response is null. Print $exec_connstatus_query and check first.
Or in case if query return Zero records, in that case loop won't run.

answered Jun 15, 2012 at 15:51

Nishu Tayal

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1 Comment

PHPSrike Over a year ago

Thanks! btw I am from India, wanna join for a project?

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