How to get and compare row values in PHP/MySQL?

Question

I would like to know what code I would need to use to get the values from a row (which would naturally have data from different columns)

I would like to check if the IP address is the same as the Poll ID. As you would expect the IP address is stored in one column, and the poll id in a next column.

  $q = mysql_query("SELECT * FROM logs");

  while($row = mysql_fetch_array($q))
  {
      if(($ip = $_SERVER['REMOTE_ADDR']) == $row['ip'])
      {
         $duplicateIP = true;
       }//end if

      if(($row['poll_id'] == 1))
      {
         $duplicatePoll = true;
       }//end if
   }//end while

I realised this code won't work as it will return the poll id to be true as long as it is equal to 1. How do I ensure that it will only return to be true if that poll id matches the IP address? Thanks.

Unless you are using $ip elsewhere there is no need to do that variable assignment in your if statement. — John Conde
– John Conde, Commented Apr 10, 2014 at 13:22
This? SELECT * FROM logs WHERE IP = $_SERVER['REMOTE_ADDR']; — Ne Ma
– Ne Ma, Commented Apr 10, 2014 at 13:29

halfer · Accepted Answer · 2014-04-10 14:43:49Z

1

Instead of:

if(($ip = $_SERVER['REMOTE_ADDR']) == $row['ip'])
{
    $duplicateIP = true;
}//end if

if(($row['poll_id'] == 1))
{
    $duplicatePoll = true;
}//end if

You should write:

if($_SERVER['REMOTE_ADDR'] == $row['ip'] && $row['poll_id'] == 1){

    $duplicateIP = true;

}//end if

Or change your query:

$q = mysql_query(
    "SELECT * FROM logs WHERE ip = '".$_SERVER['REMOTE_ADDR'] .
    "' and poll_id = '".$iPollid."' "
);

edited Apr 10, 2014 at 14:43

halfer

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answered Apr 10, 2014 at 13:33

Andrzej Reduta

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3 Comments

Diego Over a year ago

Thumbs up for putting the IP and PoolID on the query. You can also do something like "SELECT 1 AS exists FROM logs WHERE ip = '".$_SERVER['REMOTE_ADDR']."' and poll_id = '".$iPollid." LIMIT 1;'. This will return one row with a 1 in the array index "exists". It that comes empty, it does not exists on the table.

Andrzej Reduta Over a year ago

i believe LIMIT 1 is not needed. There should be 'unique' index on ip+poll_id

Diego Over a year ago

Yep. But since we don't have the schema, plan for the worst... hehe (also the table is called log, so you can expect to have multiple rows for the same ip-pollid pair). Also would be nice to add an index to that pair of columns. Cheers!

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