Why map return [] ?

[Suliman via Digitalmars-d-learn]

On Friday, 14 April 2017 at 15:35:15 UTC, cym13 wrote:
> On Friday, 14 April 2017 at 15:29:33 UTC, Suliman wrote:
>> auto x = MySQLTablesRange.map!(a=>a);
>> writeln(x);
>>
>> return: []
>>
>> while next code:
>> MySQLTablesRange.each!(a=>a.writeln);
>>
>> return data line by line.
>>
>> Why?
>
> What library is that supposed to be?

http://code.dlang.org/packages/mysql-native