Question

I have tables:

events

    -----+-------------------+
    | id | eventName         |
    -----+-------------------+
    | 1  | Bowling           |
    | 2  | Quiz              |
    | 3  | Darts             |
    | 4  | Pool              |
    | 5  | Treasure Hunt     |
    | 6  | Snooker           |
    -----+-------------------+

competitors

    ------+------------------+
    | id  | competitorName   |
    ------+------------------+
    | 1   | Microsoft        |
    | 2   | BBC              |
    | 3   | Facebook         |
    ------+------------------+

results

    ------+---------------+---------+-------------+
    | id  | competitorId  | eventId |  eventScore |
    ------+---------------+---------+-------------+
    | 1   | 1             |  1      |   12        |
    | 2   | 1             |  2      |   11        |
    | 3   | 1             |  3      |   23        |
    | 4   | 2             |  1      |   66        |
    | 5   | 2             |  2      |   12        |
    | 6   | 2             |  3      |   11        |
    | 7   | 2             |  4      |   23        |
    | 8   | 2             |  5      |   66        |
    | 3   | 2             |  6      |   23        |
    | 4   | 3             |  1      |   66        |
    | 5   | 3             |  2      |   12        |
    | 6   | 3             |  3      |   11        |
    | 7   | 3             |  4      |   23        |
    | 8   | 3             |  6      |   66        |
    ------+---------------+---------+-------------+

From which I want to achieve output like this:

    --------------+---------+---------+--------+------+--------------+----------
    | competitor  | Bowling | Quiz    |  Darts |Pool  |Treasure Hunt | Snooker | 
    --------------+---------+---------+--------+------+--------------+----------
    | Microsoft   | 12      |  11     |   23   |  0   | 0            | 0       |
    | BBC         | 66      |  12     |   11   |  23  | 66           | 23      |
    | Facebook    | 66      |  12     |   11   |  23  | 0            | 66      |
    --------------+---------+---------+--------+------+--------------+----------

I have tried all sorts of joins and nested php but I just can’t crack it. I’m not even sure if it’s possible. My SQL knowledge is not great, I’ve tried some tutorials but they don’t cover this kind of query.

Answer 1

You can create your query by php like this

<?php
$events = array('Assume this is array of events table with id,eventName as key');

$column = array();
foreach($events as $event)
{
     $column[] = 'SUM(IF(results.eventId = '.$event['id'].', results.eventScore, 0)) AS '.$event['eventName'];
}

$sql = 'SELECT   competitors.competitorName AS competitor,';
$sql .= implode(',',$column);
$sql .= ' FROM competitors';
$sql .= ' LEFT JOIN results ON results.competitorId = competitors.id';
$sql .= ' GROUP BY competitors.id';
//Put $sql into mysql_query then

Then, to get row dynamically

while($row = mysql_fetch_array($result, MYSQL_ASSOC))
{
    foreach($row as $k=>$v) 
    {
         //Here you get Column Name as $k  and data value as $v
    }
}