Look at array and count true or false from duplicate values - php

Question

I have a table in SQL, where users can answer many times (the same users and different users). I want to count how many true or false values there are.
For example, like user 1 has 5 rows in my table, 3 times true, and 2 times false and user 9 has got 10 true and 1 false like that but I would not know what user numbers.
I would like output like
User 1 - 5x True 1x False, User 4 1x True 3x False etc. But I would not know what user and the user list can grow.

Answer 1

there is a simple (not recommended) solution using a loop:
$resultq = mysql_query('select value, user_id from answers');
$answers_per_user = array(); // positive answers per user
$totals_per_user = array(); // total answers per user
while($result = mysql_fetch_assoc($resultq)){
if($result['answer'])
$answers_per_user[$result['user_id']] += $result['answer']; // increment positive answer counter for user
$totals_per_user[$result['user_id']]++;
}
you would have an array holding positive answers per user and total answers per users which you can then use to calculate negative answers
the recommended solution is to use a group by sql statement that gives you all the calculated information.
$result = mysql_query('select sum(value) as positivecount, count(*) as total, user_id from answers group by user_id');
while($data = mysql_fetch_assoc($result)){
// $data will hold positivecount,total, and user_id giving you all the data you need for calculating negative answer values.
}
// alternatively, use a query like this for counting the answers that were 'beans':
// select sum(if(value = "beans", 1, 0)) as answered_beans, count(*) as total, user_id from answers group by user_id
see: http://dev.mysql.com/tech-resources/articles/wizard/page3.html

Answer 2

The most elegant solution for this problem is to actually have two SQL tables; one with one row for each user (userID, username, etc.) and one for each vote, wich could be multiple per user.
The following example will echo some information about the data.
<?php
$sqlusers = mysql_query("SELECT userid FROM user_table")//This line grabs all users from the database.
$users = mysql_fetch_array($sqlusers);//This line creates an array containing all users.
foreach($users as $key=>$currentuser){
$sqlvotes = mysql_query("SELECT userid, vote FROM vote_table WHERE userid = $currentuser[userid]");
$votes = mysql_fetch_array($sqlvotes);//obtain an array of votes the current user has submitted
$votefrequency = array_count_values($votes)//counts the amount of trues and falses in the $votes array, and returns an array with the [true] and [false] indexes containing their respective frequency.
echo "user ".$userid." has voted ".$votefrequency[true]." times true and ".$votefrequency[false]." times false/n";
echo "average vote:". (($votefrequency[true] - $votefrequency[false] > 0) ? "true" : "false" );
}