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 │   │
└────────────┴───┴───┘
```

if (func->getKind() == FunctionWithOptionalConstArg::Kind::LEFT_CONST)
                        buf << applyVisitor(FieldVisitorToString(), (*func->getConstArg().column)[0]) << ", ";
                }
            }
        }
        buf << column_name;
        for (auto it = monotonic_functions_chain.rbegin(); it != monotonic_functions_chain.rend(); ++it)
        {
            if (print_constants)
            {
                if (const auto * func = typeid_cast<const FunctionWithOptionalConstArg *>(it->get()))
                {
                    if (func->getKind() == FunctionWithOptionalConstArg::Kind::RIGHT_CONST)
                        buf << ", " << applyVisitor(FieldVisitorToString(), (*func->getConstArg().column)[0]);
                }
            }
            buf << ")";
        }
    };
    WriteBufferFromOwnString buf;
    switch (function)
    {
        case FUNCTION_AND:
            return "and";
        case FUNCTION_OR:
            return "or";
        case FUNCTION_NOT:
            return "not";
        case FUNCTION_UNKNOWN:
            return "unknown";