**Describe the bug**
Under certain conditions the equals comparison between String and Date yields the wrong result. Range Comparisons with greather-than-equals returns the correct result set.

**How to reproduce**
* Which ClickHouse server version to use: 21.2.5.5 (latest at the time of this issue)
* Which interface to use, if matters: HTTP (but should not matter)

```sql
CREATE TABLE default.myTable (
	myDay Date,
	myOrder Int32,
	someData String
) 
ENGINE = ReplacingMergeTree
PARTITION BY floor(toYYYYMMDD(myDay), -1)
ORDER BY (myOrder)
;

INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-01', 1);
INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-02', 2); // This row should be returned
INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-03', 3);

SELECT * FROM default.myTable mt
WHERE myDay = '2021-01-02';
```

**Expected behavior**
The last query in the example should yield the marked row. Instead it returns a empty result set.

There must be a connection to the used `PARTITION KEY`. The issue fails to reproduce as soon as I do any changes to the `PARTITION KEY` setting.

{
public:
    enum Kind
    {
        NO_CONST = 0,
        LEFT_CONST,
        RIGHT_CONST,
    };
    explicit FunctionWithOptionalConstArg(const FunctionBasePtr & func_) : func(func_) {}
    FunctionWithOptionalConstArg(const FunctionBasePtr & func_, const ColumnWithTypeAndName & const_arg_, Kind kind_)
        : func(func_), const_arg(const_arg_), kind(kind_)
    {
    }
    String getName() const override { return func->getName(); }
    const DataTypes & getArgumentTypes() const override { return func->getArgumentTypes(); }
    const DataTypePtr & getResultType() const override { return func->getResultType(); }
    ExecutableFunctionPtr prepare(const ColumnsWithTypeAndName & arguments) const override { return func->prepare(arguments); }