How to use database BETWEEN query?
You can use BETWEEN like this:

$query-&gt;condition('myfield', array(5, 10), 'BETWEEN');


In your case:

$query-&gt;condition('paiddate', array('2017/03/01', '2017/03/30'), 'BETWEEN');


For more information see the Conditional Clauses documentation.

It depends on how your dates are stored as to what min and max values you should pass in.

For example it could be a unix timestamp or it could be an actual date.
I would recommend doing a more generic select on the data to find out the format of the dates and then replicate that format in the values that you are passing in.