+=head1 CLASS METHODS
+
+=over 4
+
+=item unapplied_sql
+
+Returns an SQL fragment to retreive the unapplied amount.
+
+=cut
+
+sub unapplied_sql {
+ my ($class, $start, $end) = @_;
+ my $credit_start = $start ? "AND cust_credit_refund._date <= $start" : '';
+ my $credit_end = $end ? "AND cust_credit_refund._date > $end" : '';
+ my $pay_start = $start ? "AND cust_pay_refund._date <= $start" : '';
+ my $pay_end = $end ? "AND cust_pay_refund._date > $end" : '';
+
+ "refund
+ - COALESCE(
+ ( SELECT SUM(amount) FROM cust_credit_refund
+ WHERE cust_refund.refundnum = cust_credit_refund.refundnum
+ $credit_start $credit_end )
+ ,0
+ )
+ - COALESCE(
+ ( SELECT SUM(amount) FROM cust_pay_refund
+ WHERE cust_refund.refundnum = cust_pay_refund.refundnum
+ $pay_start $pay_end )
+ ,0
+ )
+ ";