presto-main/src/main/java/io/prestosql/type/VarcharOperators.java/VarcharOperators/greaterThan
class VarcharOperators:    @LiteralParameters("x")
    @ScalarOperator(GREATER_THAN)
    @SqlType(StandardTypes.BOOLEAN)
    public static boolean greaterThan(@SqlType("varchar(x)") Slice left, @SqlType("varchar(x)") Slice right)
    {
        return left.compareTo(right) > 0;
    }