21.5.1
```sql

create table test(d Date, k Int64, s String) 
Engine=MergeTree partition by (toYYYYMM(d),k) order by (d, k)

insert into test values ('2020-01-01', 1, '');
insert into test values ('2020-01-02', 1, '');

SELECT * FROM test WHERE d != '2020-01-01'
0 rows in set. Elapsed: 0.003 sec.


SELECT * FROM test WHERE identity(d) !=  '2020-01-01';
┌──────────d─┬─k─┬─s─┐
│ 2020-01-02 │ 1 │   │
└────────────┴───┴───┘

SELECT * FROM test WHERE toDate(d) != '2020-01-01';
┌──────────d─┬─k─┬─s─┐
│ 2020-01-02 │ 1 │   │
└────────────┴───┴───┘
```

},
    {
        "empty",
        [] (RPNElement & out, const Field & value)
        {
            if (value.getType() != Field::Types::String)
                return false;
            out.function = RPNElement::FUNCTION_IN_RANGE;
            out.range = Range("");
            return true;
        }
    },
    {
        "notEmpty",
        [] (RPNElement & out, const Field & value)
        {
            if (value.getType() != Field::Types::String)
                return false;
            out.function = RPNElement::FUNCTION_NOT_IN_RANGE;
            out.range = Range("");
            return true;
        }
    },
    {
        "like",
        [] (RPNElement & out, const Field & value)
        {
            if (value.getType() != Field::Types::String)
                return false;
            String prefix = extractFixedPrefixFromLikePattern(value.get<const String &>());