attach 'similarity.db' as similarity;
attach 'digikam4.db' as digikam4;

SELECT (a1.identifier || a1.relativePath || '/' || x.di1_name) AS Image1,
       (a2.identifier || a2.relativePath || '/' || x.di2_name) AS Image2
FROM (SELECT similarity.ImageSimilarity.value, di1.name AS di1_name, di1.album AS di1_album, di2.name AS di2_name, di2.album AS di2_album
      FROM similarity.ImageSimilarity
      JOIN digikam4.Images AS di1 ON di1.id = imageid1
      JOIN digikam4.Images AS di2 ON di2.id = imageid2
      WHERE value=1.0
     ) AS x
JOIN (SELECT a.id, ar.identifier,relativePath
      FROM digikam4.Albums AS a
      JOIN digikam4.AlbumRoots AS ar ON ar.id = a.albumRoot
     ) AS a1 ON a1.id = di1_album
JOIN (SELECT a.id, ar.identifier,relativePath
      FROM digikam4.Albums AS a
      JOIN digikam4.AlbumRoots AS ar ON ar.id = a.albumRoot
     ) AS a2 ON a2.id = di2_album;