mysql - Calculate average age of members (PHP) -

i want create average age of members. managed array of date of births , found easy way calculate birthday. don't manage combine it.

my 'date of birth' - array:

$results = array();  $dob_array = mysqli_query($conn, "select dob_array members");      while($row = mysqli_fetch_assoc($dob_array)){         $results[] = $row;     } 

the calculation of age:

$today = new datetime(); $birthdate = new datetime("1991-01-01"); $interval = $today->diff($birthdate); echo $interval->format('%y years'); 

calculation average of age-array:

$average = array_sum($array) / count($array); 

might done direct sql (using timestampdiff() , avg() functions):

select avg(timestampdiff(year, `dob`, now())) `average` `member`;