Always reproduced:

```
milovidov-desktop :) create table table_map (a Map(String, String), b String) engine = MergeTree() order by a;

CREATE TABLE table_map
(
    `a` Map(String, String),
    `b` String
)
ENGINE = MergeTree
ORDER BY a

Query id: 8f8120c1-c165-452a-815f-2bcae3957e2a

Ok.

0 rows in set. Elapsed: 0.002 sec. 

milovidov-desktop :) SELECT b FROM table_map WHERE a = map('name', NULL, '', NULL)

SELECT b
FROM table_map
WHERE a = {'name', NULL, '', NULL}
```
}
};
/** Conversion of Date or DateTime to DateTime64: add zero sub-second part.
  */
template <typename Name> struct ConvertImpl<DataTypeDate, DataTypeDateTime64, Name, ConvertDefaultBehaviorTag>
    : DateTimeTransformImpl<DataTypeDate, DataTypeDateTime64, ToDateTime64Transform> {};
template <typename Name> struct ConvertImpl<DataTypeDateTime, DataTypeDateTime64, Name, ConvertDefaultBehaviorTag>
    : DateTimeTransformImpl<DataTypeDateTime, DataTypeDateTime64, ToDateTime64Transform> {};
/** Transformation of numbers, dates, datetimes to strings: through formatting.
  */
template <typename DataType>
struct FormatImpl
{
    static void execute(const typename DataType::FieldType x, WriteBuffer & wb, const DataType *, const DateLUTImpl *)
    {
        writeText(x, wb);
    }
};
template <>
struct FormatImpl<DataTypeDate>
{
    static void execute(const DataTypeDate::FieldType x, WriteBuffer & wb, const DataTypeDate *, const DateLUTImpl *)
    {
        writeDateText(DayNum(x), wb);
    }
};
template <>
struct FormatImpl<DataTypeDateTime>
{
    static void execute(const DataTypeDateTime::FieldType x, WriteBuffer & wb, const DataTypeDateTime *, const DateLUTImpl * time_zone)