Some time in the 4.x release series, the Dates view stopped showing any images when using an external MYSQL server.  I have been checking every release since about 4.10.

Using 5.2.0 (phillip5 PPA packages on Ubuntu 16.10) I see the following error on the console whenever the Dates view is selected.

digikam.dbengine: Failure executing query:
 "SELECT DISTINCT Images.id, Images.name, Images.album, Albums.albumRoot,
    ImageInformation.rating, Images.category, ImageInformation.format,
    ImageInformation.creationDate, Images.modificationDate, Images.fileSize,
    ImageInformation.width, ImageInformation.height
  FROM Images 
    LEFT JOIN ImageInformation ON Images.id=ImageInformation.imageid
    INNER JOIN Albums ON Albums.id=Images.album
  WHERE Images.status=1
    AND ImageInformation.creationDate < '2016-11-01T00:00:00'
    AND ImageInformation.creationDate >= '2016-10-01T00:00:00'
  ORDER BY Albums.id;" 
Error messages: "QMYSQL: Unable to execute query" "Expression #1 of ORDER BY clause is not in SELECT list, references column 'kam_core_5.Albums.id' which is not in SELECT list; this is incompatible with DISTINCT" 3065 2 
Bound values:  (QVariant(QString, "2016-11-01T00:00:00"), QVariant(QString, "2016-10-01T00:00:00"))

Clearly from the error message the ORDER BY is incorrect (at least for MYSQL).
I have not checked if this syntax works with SQLITE, I can only imagine it does otherwise this bug would have been raised already!

FIX
Changing the ORDER BY clause to use Images.album (which IS in the select list):

   ORDER BY Images.album;

works perfectly when executed as a direct query against the database. 

As a bonus request: Can we have a DatesView component in the bug tracker ?