presto-main/src/main/java/io/prestosql/sql/planner/LiteralInterpreter.java/LiteralInterpreter/visitIntervalLiteral
class LiteralInterpreter:        @Override
        protected Long visitIntervalLiteral(IntervalLiteral node, ConnectorSession session)
        {
            if (node.isYearToMonth()) {
                return node.getSign().multiplier() * parseYearMonthInterval(node.getValue(), node.getStartField(), node.getEndField());
            }
            else {
                return node.getSign().multiplier() * parseDayTimeInterval(node.getValue(), node.getStartField(), node.getEndField());
            }
        }