Description:
------------
When you have array with text index-es(hash) and when you extract this array to variables if some of array columns have null value variable for this column do not clears.
For example in code reproduce :
if for example column "keyword" is null for some row variable $keyword after extracting do not clears.

Reproduce code:
---------------
$query = "SELECT
						a.agent_sid,
            a.country_sid,
            a.region_sid,
						a.keyword,
						a.agent_frequency_sid,
						a.last_email,
						u.email,
						CONCAT(u.first_name, ' ', u.last_name) as fullname
					FROM
						AGENT a INNER JOIN USER u
					ON
						a.user_sid=u.user_sid INNER JOIN OBJECT_HISTORY o
					ON
						u.object_history_sid=o.object_history_sid
					WHERE
						o.object_status_sid=1
					AND
						(a.agent_frequency_sid=2 OR agent_frequency_sid=DAYOFWEEK(DATE_ADD(CURDATE(), INTERVAL -1 DAY))+2)
					";

$agent_result = query($query);while ($row = mysql_fetch_array($agent_result,MYSQL_ASSOC)) {
	extract($row);
};


Expected result:
----------------
to fech result into array and then to extract array into variables for each row and if cell empty or null variable be empty too.

Actual result:
--------------
variable do not clears