+=item _money_table_where TABLE START_TIME [ END_TIME [ OPTION => VALUE ... ] ]
+
+Helper method for balance_date_sql; name (and usage) subject to change
+(suggestions welcome).
+
+Returns a WHERE clause for the specified monetary TABLE (cust_bill,
+cust_refund, cust_credit or cust_pay).
+
+If TABLE is "cust_bill" or the unapplied_date option is true, only
+considers records with date earlier than START_TIME, and optionally not
+later than END_TIME .
+
+=cut
+
+sub _money_table_where {
+ my( $class, $table, $start, $end, %opt ) = @_;
+
+ my @where = ();
+ push @where, "cust_main.custnum = $table.custnum" unless $opt{'total'};
+ if ( $table eq 'cust_bill' || $opt{'unapplied_date'} ) {
+ push @where, "$table._date <= $start" if defined($start) && length($start);
+ push @where, "$table._date > $end" if defined($end) && length($end);
+ }
+ push @where, @{$opt{'where'}} if $opt{'where'};
+ my $where = scalar(@where) ? 'WHERE '. join(' AND ', @where ) : '';
+
+ $where;
+
+}
+