PHP+MySQL join statement arrange multiple values as row in mysql_fetch array

Question

I am using a MySQL INNER JOIN statement which returns various results for one distinct record in the main table from the joins, similar to How to Join Multiple Joins yet return Distinct Values My query is

SELECT  cl.*, dep.dept_name  
FROM epapers.clientelle  cl 
INNER JOIN  epapers.dept_staff_users depu 
ON depu.user_id=cl.user_id 
INNER JOIN epapers.dept dep 
ON dep.dept_id=depu.dept_id 
group by cl.user_id 
ORDER BY cl.user_name ASC, 

I would like to display the above in a table shown below

echo "<tr bgcolor='#CCCCCC'>
<td >$num</td><td >".$row[user_id]."</td><td>".$row[user_name]."</td>
<td >".$row[fname]."</td><td >".$row[lname]."</td>
 <td >".$row[dept_name]."</td>
 <td >".$row[dept_name]."</td>
 <td >".$row[dept_name]."</td>
 <td >".$row[email]."</td>";
 $TrID = "$row[user_id]";
 echo "<td >";
 echo '<form name="activate" action="activate_acc.php" method="POST" ;">';
 echo "<input type='hidden' name='TrID' value='$TrID'>";    
 echo "<input type='checkbox' name='active' value='$row[active]'>"; 
 echo '<input type="submit" name="Submit" value="Delete">';
 echo '</form>';
 echo "</td >";
 ...

Note the the departments can be upto 3 departments. How do I return the mysql query results in a single row for the departments?

Answer 1

If you are using MySQL you can use GROUP_CONCAT but you will have to do some post processing and it's a bit ugly.

SELECT  cl.*, GROUP_CONCAT( DISTINCT dep.dept_name SEPARATOR '|' ) as dept_name 
FROM epapers.clientelle  cl 
INNER JOIN  epapers.dept_staff_users depu 
ON depu.user_id=cl.user_id 
INNER JOIN epapers.dept dep 
ON dep.dept_id=depu.dept_id 
group by cl.user_id 
ORDER BY cl.user_name ASC



foreach( ....
    $departments = explode( '|', $row['dept_name'] );
...
    if( isset( $departments[0] ) ) {
        echo "<td>{$departments[0]}</td>";
    } else {
        echo "<td></td>";
    }
    // same check
    echo "<td>{$departments[1]}</td>";
    // same check
    echo "<td>{$departments[2]}</td>";

It's kinda denormalisation at runtime...

Answer 2

well the way you can do it with a mysql query is to join the table for each of the three departments, such as this: select a.dept_id as dept_1 b.dept_id as dept_2 etc and join the same table with different for each dept id. this way is very processor intensive though. It would be a lot faster to get the data the way you have your query written, and then process the data with a function prior to using it. here is a simple example of how i would do it:

function prep_data($mysql_result)
{    
    $results = array();
    $work = array();
    while ($row = mysql_fetch_assoc($mysql_result))
    {
        if ($work['user_id'] == $row['user_id'])
        {
            // just add dept data to dept array
            $dept[] = $row['dept_id'];
        }
        else
        {
            // data changed            
            if (isset($work['user_id']))
            {
                // assign dept array to data array
                $work['dept_id'] = $dept;
                // add work array to results collection
                array_push($results, $work);                
                // start working with the new user_id
                $work = $row;
                $dept = array($row['dept_id']);
                continue;                
            } 
            else
            {
                // this is first pass.  grab the row data and start the dept[] array;
                $work = $row;
                $dept = array($row['dept_id']);
                continue;
            }
        }
    }
    $work['dept_id'] = $dept;
    array_push($results, $work);
    return($results);
}

// good luck