Hello reader's If you are using codeigniter and want to make '<=' mysql query then you can use the code syntax as below:-

->select('COUNT(payment.keyid) AS rec_count')   
->where('payment.paymentdate >=', $month_start)
->where('payment.paymentdate <=', $month_end)
->get()

here you just have to add the line

  ->where('payment.paymentdate >=', $month_start)

And similarly you can make joins or ordery by clauses also as example below:-

->select('product_key.client_name, product_key.contact_email, product_key.status, product_key.id, payment.paymentdate, (payment.id) as pid,payment.subscription_type')
->from('product_key')         
->join('payment', 'payment.keyid=product_key.id', 'left outer') 
->where('status', 'purchased')
->order_by('client_name', "asc")
->group_by('product_key.id')