case CUBRID:
case MYSQL: {
Interval interval = rhsAsInterval();
if (operator == SUBTRACT) {
interval = interval.neg();
}
if (rhs.get(0).getType() == YearToMonth.class) {
return field("{date_add}({0}, {interval} {1} {year_month})", getDataType(), lhs, val(interval, String.class));
}