21.2:

```
milovidov-desktop :) SELECT CAST(1111111111.222 AS DateTime64(3))

SELECT cast(1111111111.222, 'DateTime64(3)')

Query id: d10c8623-5c74-4a38-b535-a99f6af4d28d

┌─cast(1111111111.222, 'DateTime64(3)')─┐
│               2005-03-18 04:58:31.222 │
└───────────────────────────────────────┘
```

master:

```
milovidov-desktop :) SELECT CAST(1111111111.222 AS DateTime64(3))

SELECT cast(1111111111.222, 'DateTime64(3)')

Query id: cb4af967-a4ae-4df5-89ba-234d68675f93

┌─cast(1111111111.222, 'DateTime64(3)')─┐
│               2005-03-18 04:58:31.000 │
└───────────────────────────────────────┘
```
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeDateTime64.h>
#include <DataTypes/DataTypeEnum.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/DataTypeMap.h>
#include <DataTypes/DataTypeNullable.h>
#include <DataTypes/DataTypeNothing.h>
#include <DataTypes/DataTypeUUID.h>
#include <DataTypes/DataTypeInterval.h>
#include <DataTypes/DataTypeAggregateFunction.h>
#include <Formats/FormatSettings.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnFixedString.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnNullable.h>
#include <Columns/ColumnTuple.h>
#include <Columns/ColumnMap.h>
#include <Columns/ColumnsCommon.h>
#include <Common/FieldVisitors.h>
#include <Common/assert_cast.h>
#include <Common/quoteString.h>
#include <Core/AccurateComparison.h>
#include <Functions/IFunctionAdaptors.h>
#include <Functions/FunctionsMiscellaneous.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/DateTimeTransforms.h>
#include <Functions/toFixedString.h>
#include <DataTypes/DataTypeLowCardinality.h>