MySQL Join two tables with comma separated values

I have 2 tables as below

Notes Table

╔══════════╦═════════════════╗
║ nid      ║    forDepts     ║
╠══════════╬═════════════════╣
║ 1        ║ 1,2,4           ║
║ 2        ║ 4,5             ║
╚══════════╩═════════════════╝

Positions Table

╔══════════╦═════════════════╗
║ id       ║    name         ║
╠══════════╬═════════════════╣
║ 1        ║ Executive       ║
║ 2        ║ Corp Admin      ║
║ 3        ║ Sales           ║
║ 4        ║ Art             ║
║ 5        ║ Marketing       ║
╚══════════╩═════════════════╝

I am looking to query my Notes table and associate the 'forDepts' column with values from the Positions table.

The output should be:

    ╠══════════╬════════════════════════════╣
    ║ 1        ║ Executive, Corp Admin, Art ║
    ║ 2        ║ Art, Marketing             ║
    ╚══════════╩════════════════════════════╝

I know that the database should be normalized but I cannot change the database structure for this project.

This is going to be used to export a excel file with the code below.

<?PHP

	$dbh1 = mysql_connect($hostname, $username, $password); 
	mysql_select_db('exAdmin', $dbh1);


	function cleanData(&$str)
  {
    $str = preg_replace("/\t/", "\\t", $str);
    $str = preg_replace("/\r?\n/", "\\n", $str);
    if(strstr($str, '"')) $str = '"' . str_replace('"', '""', $str) . '"';
  }
	
	$filename = "eXteres_summary_" . date('m/d/y') . ".xls";
	
	header("Content-Disposition: attachment; filename=\"$filename\"");
	header("Content-Type: application/vnd.ms-excel");
	//header("Content-Type: text/plain");
	
	$flag = false;


	$result = mysql_query(
	"SELECT p.name, c.company, n.nid, n.createdOn, CONCAT_WS(' ',c2.fname,c2.lname), n.description 
	 FROM notes n 
	 LEFT JOIN Positions p ON p.id = n.forDepts
	 LEFT JOIN companies c ON c.userid = n.clientId
	 LEFT JOIN companies c2 ON c2.userid = n.createdBy"
	 , $dbh1);
 

	
	while(false !== ($row = mysql_fetch_assoc($result))) {
		if(!$flag) {
			$colnames = array(
				'Created For' => "Created For",
				'Company' => "Company",
				'Case ID' => "Case ID",
				'Created On' => "Created On",
				'Created By' => "Created By",
				'Description' => "Description"
			);
			// display field/column names as first row
	 		echo implode("\t", array_keys($colnames)) . "\r\n";
			$flag = true;
	}
	

		$row['createdOn'] = date('m-d-Y | g:i a', strtotime($row['createdOn']));
	
    array_walk($row, 'cleanData');
    echo implode("\t", array_values($row)) . "\r\n";
  }
  exit;
  
  ?>

This code outputs only the first value of 'forDepts'

Exa: Executive (instead of Executive, Corp Admin, Art)

Can this be accomplished by CONCAT or FIND_IN_SET?

Please help! Thanks in advance!

SELECT	a.nid,
		GROUP_CONCAT(b.name ORDER BY b.id) DepartmentName
FROM	Notes a
		INNER JOIN Positions b
			ON FIND_IN_SET(b.id, a.forDepts) > 0
GROUP	BY a.nid

• SQLFiddle Demo

Table 1
╔══════════╦═════════════════╗
║ nid      ║    forDepts     ║
╠══════════╬═════════════════╣
║ 1        ║ 1,2,4           ║
║ 2        ║ 4,5             ║
╚══════════╩═════════════════╝
Table 2
╔══════════╦═════════════════╗
║ id       ║    name         ║
╠══════════╬═════════════════╣
║ 1        ║ Executive       ║
║ 2        ║ Corp Admin      ║
║ 3        ║ Sales           ║
║ 4        ║ Art             ║
║ 5        ║ Marketing       ║
╚══════════╩═════════════════╝

SELECT * FROM table1 as t1 LEFT JOIN table2 as t2 ON find_in_set(t2.id, 
t1.forDepts)

Output 

 ╠══════════╬════════════════════════════╣
 ║ 1        ║ Executive, Corp Admin, Art ║
 ║ 2        ║ Art, Marketing             ║
 ╚══════════╩════════════════════════════╝