Grouping & Adding my query results together

Once I query my MYSQL database I need to take the results and add the records with the same salesperson. Right now here is my PHP:

<?php$query="(SELECT `sales_person_1` AS sales_person, SUM(`system_size`)*`commission1` AS commission  FROM `pv_jobs` WHERE x_sales_mgr ='2' GROUP BY sales_person)UNION(SELECT `sales_person_2` AS sales_person, SUM(`system_size`)*`commission2` AS commission FROM `pv_jobs` WHERE x_sales_mgr ='2' GROUP BY sales_person)UNION(SELECT `sales_person_3` AS sales_person, SUM(`system_size`)*`commission3` AS commission  FROM `pv_jobs` WHERE x_sales_mgr ='2' GROUP BY sales_person)UNION(SELECT `sales_person_4` AS sales_person, SUM(`system_size`)*`commission4` AS commission  FROM `pv_jobs` WHERE x_sales_mgr ='2' GROUP BY sales_person) ORDER BY commission DESC ";
$result = mysql_query($query) or die(mysql_error());
while($row = mysql_fetch_array($result)){		echo $row['sales_person']. " Has Sold " .$row['commission']. " Watts!"; 	echo "<br />";}?>

And here is the results:

Sales Person 1 Has Sold 1000 Watts!
Sales Person 3 Has Sold 1000 Watts!
Sales Person 3 Has Sold 1000 Watts!
Sales Person 2 Has Sold 1000 Watts!
Sales Person 1 Has Sold 1000 Watts!
Sales Person 4 Has Sold 1000 Watts!
Sales Person 6 Has Sold 1000 Watts!
Sales Person 2 Has Sold 1000 Watts!
Sales Person 3 Has Sold 1000 Watts!
Sales Person 1 Has Sold 1000 Watts!
Sales Person 1 Has Sold 1000 Watts!
Sales Person 6 Has Sold 1000 Watts!
Sales Person 6 Has Sold 1000 Watts!
Sales Person 2 Has Sold 1000 Watts!
Sales Person 3 Has Sold 1000 Watts!
Sales Person 1 Has Sold 1000 Watts

I need my code to find the similar salesperson name and add the commission together to give me a total like:

Sales Person 1 Has Sold 100000 Watts!
Sales Person 2 Has Sold 100000 Watts!
Sales Person 3 Has Sold 100000 Watts!
Sales Person 4 Has Sold 100000 Watts!
Sales Person 5 Has Sold 100000 Watts!
Sales Person 6 Has Sold 100000 Watts!

Can anyone help?

Thanks