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 │
└───────────────────────────────────────┘
```
{
                throw Exception("Illegal column " + named_from.column->getName() + " of first argument of function " + Name::name,
                    ErrorCodes::ILLEGAL_COLUMN);
            }
        }
        if (const ColVecFrom * col_from = checkAndGetColumn<ColVecFrom>(named_from.column.get()))
        {
            typename ColVecTo::MutablePtr col_to = nullptr;
            if constexpr (IsDataTypeDecimal<ToDataType>)
            {
                UInt32 scale;
                if constexpr (std::is_same_v<Additions, AccurateConvertStrategyAdditions>
                    || std::is_same_v<Additions, AccurateOrNullConvertStrategyAdditions>)
                {
                    scale = additions.scale;
                }
                else
                {
                    scale = additions;
                }
                col_to = ColVecTo::create(0, scale);
            }
            else
                col_to = ColVecTo::create();
            const auto & vec_from = col_from->getData();
            auto & vec_to = col_to->getData();
            size_t size = vec_from.size();
            vec_to.resize(size);
            ColumnUInt8::MutablePtr col_null_map_to;
            ColumnUInt8::Container * vec_null_map_to [[maybe_unused]] = nullptr;