ruby on rails - Arel AND clause and Empty condition -

consider following code fragment:

def sql   billing_requests   .project(billing_requests[arel.star])   .where(     filter_by_day       .and(filter_by_merchant)       .and(filter_by_operator_name)   )   .to_sql end  def filter_by_day   billing_requests[:created_at].gteq(@start_date).and(     billing_requests[:created_at].lteq(@end_date)   ) end  def filter_by_operator_name   unless @operator_name.blank?     return billing_requests[:operator_name].eq(@operator_name)   end end  def filter_by_merchant   unless @merchant_id.blank?     return billing_requests[:merchant_id].eq(@merchant_id)   end end  private  def billing_requests   @table ||= arel::table.new(:billing_requests) end 

in method filter_by_merchant when merchant id becomes empty, should value must returned arel ignore , clause effect? also, there better way handle case?

you should return true. when run .and(true) converted 'and 1' in sql.

def filter_by_merchant   return true if @merchant_id.blank?    billing_requests[:merchant_id].eq(@merchant_id) end