PHP get largest number from mysql table

Question

i have counted the number of voters that voted for certain candidate i want to display which one got the highest voting number. i tried to store them in variables so i can use max() method but i got the error "undefined ".any help please

  <?php 
 $query="select count(*) as total from voting Where ca_id=1";
  //ca_id is the candidate id that voter choose
 $result = mysql_query($query);
 $row = mysql_fetch_assoc($result);
 echo"$row[total]<br>";


 $query="select count(*) as total2 from voting Where ca_id=2";
 $result = mysql_query($query);
 $row2 = mysql_fetch_assoc($result);
 echo"$row2[total2]<br>";

 $query="select count(*) as total3 from voting Where ca_id=3";
 $result = mysql_query($query);
 $row3 = mysql_fetch_assoc($result);
 echo"$row3[total3]<br>";

 $query="select count(*) as total4 from voting Where ca_id=5";
 $result = mysql_query($query);
 $row4 = mysql_fetch_assoc($result);
 echo"$row4[total4]<br>";



?>

Answer 1

SELECT count(1) co, ca_id FROM voting GROUP BY ca_id ORDER BY co DESC LIMIT 5

Answer 2

You don't need to perform four queries for this. You could just use a single query. In your case, you could do:

select ca_id, count(*) as counter from voting group by ca_id order by counter desc

And you can get your result with a single query

As mentioned, PDO is a better alternative in this case for your database-related calls

Answer 3

Please, don't use mysql_* functions in new code. They are no longer maintained and the deprecation process has begun on it. See the red box ? Learn about prepared statements instead, and use PDO or MySQLi - this article will help you decide which.

You could use something like which uses the MySQLi extension.

<?php

$mysqli = new mysqli('host', 'user', 'pass', 'db');

$sql   = "SELECT COUNT(votes) as vote_count, ca_id as candidate_id FROM voting GROUP BY ca_id ORDER BY vote_count DESC";
$result= $mysqli -> query($sql);

// Error Checking
if($mysqli -> error){
   echo 'Error: '.$mysqli -> error;
   exit;
}

while($row = $result -> fetch_object()){

   // Print out each candidate ID and the amount of votes they had.
   echo 'Candidate ID: '.$row -> candidate_id.', Votes: '.$row -> vote_count.'<br/>';

   // If you want to just show the highest voted candidate - put the data in an array
   $votes[$row -> vote_count] = $row -> candidate_id;

}

echo max(array_keys($votes));

This will also cut the amount of queries your running down to just 1.

Answer 4

first of all use group by to retrieve all data in one query, instead of querying for each of the candidates:

SELECT ca_id, count(*) as total FROM voting GROUP BY ca_id

if you need a top voted id use:

SELECT ca_id, count(*) as total FROM voting GROUP BY ca_id SORT BY total 
DESC LIMIT 1

Note: not the most efficient solution but will be way faster then querying for each ca_id.