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 │   │
└────────────┴───┴───┘
```

ColumnPtr
    execute(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count, bool dry_run) const override
    {
        if (kind == Kind::LEFT_CONST)
        {
            ColumnsWithTypeAndName new_arguments;
            new_arguments.reserve(arguments.size() + 1);
            new_arguments.push_back(const_arg);
            for (const auto & arg : arguments)
                new_arguments.push_back(arg);
            return func->prepare(new_arguments)->execute(new_arguments, result_type, input_rows_count, dry_run);
        }
        else if (kind == Kind::RIGHT_CONST)
        {
            auto new_arguments = arguments;
            new_arguments.push_back(const_arg);
            return func->prepare(new_arguments)->execute(new_arguments, result_type, input_rows_count, dry_run);
        }
        else
            return func->prepare(arguments)->execute(arguments, result_type, input_rows_count, dry_run);
    }
    bool isDeterministic() const override { return func->isDeterministic(); }
    bool isDeterministicInScopeOfQuery() const override { return func->isDeterministicInScopeOfQuery(); }
    bool hasInformationAboutMonotonicity() const override { return func->hasInformationAboutMonotonicity(); }
    IFunctionBase::Monotonicity getMonotonicityForRange(const IDataType & type, const Field & left, const Field & right) const override
    {
        return func->getMonotonicityForRange(type, left, right);
    }
    Kind getKind() const { return kind; }
    const ColumnWithTypeAndName & getConstArg() const { return const_arg; }