Counting Years

mrhinman

Got a new one here I could use a little help with.

One of my clients collects EEO data as part of its employment process. The forms are generated and stored in a mysql table.

I want to be able to create statistical data based on the birth dates, which are stored as YYYY-MM-DD dates.

Each row in the table is keyed by the applicant's SSN, then has other data besides birth date. I want to be able to determine age (simple math there), then count how many records fall into the 18 to 35, 35 to 45, etc. categories.

I can easily do $age = date("Y") - substr($birth,0,4); to get an age, but I need to be able to count those. Do I need an array or what? Some examples would be helpful.

--
M

Pieman86

mrhinman wrote:
I can easily do $age = date("Y") - substr($birth,0,4); to get an age, but I need to be able to count those. Do I need an array or what? Some examples would be helpful.

Be careful...that only works correctly if the person's birthday is on January 1st (although you may not care about being completely accurate).

Yes, you can count using arrays. For example (this isn't quite valid PHP, obviously):

 
$counts = array();
for(every person in MySQL table)
{
   $age = // your age calculation function goes here
   $counts["$age"]++;
}

That will build an array so that if you enter an age, e.g. $counts[18], it will return the number of 18-year-olds. If you want to find ages over a range, say 18 to 35 inclusive, you could use:

$count = 0;
for($i = 18; $i <= 35; $i++)
{
   $count += $counts["$i"];
}