This one caught me out for a good while - I’ve got my own data stored in a database using Drupal’s Schema API and one field I want is a date, so I used the ‘datetime’ type. But whenever I came to use a value anywhere I couldn’t get any of Drupal’s date formatting functions to work - they were expecting a unix timestamp (makes sense) but the Schema API uses ‘datetime’ as a field type on MySQL so was getting a MySQL date string in return.

The answer was not to use datetime as a schema type, but int, and when passing data make sure you pass a timestamp. format_data() and views_handler_field_date etc. will then work as expected.

But it makes you wonder who left this mantrap lying around for foolhardy developers like me to fall into?