title: Convert 3 columns (day,month,year) to PHP Date/Timestamp
body: <p>I have a database with 3 columns, all VARCHAR(20)</p>
  
  <pre><code>dob_day
  dob_month
  dob_year
  </code></pre>
  
  <p>how can i convert these into a PHP Date/Timestamp and get the age of a person (the row)</p>
  
  <p>for example, if i had the following:</p>
  
  <pre><code>dob_day = 07
  dob_month = 08
  dob_year = 1994
  </code></pre>
  
  <p>this needs to display 19 as the user will be 19 years of age</p>