Question 3 

• banner_fragment.csv
• fragment_sort_bin.csv
• sort_bin.csv
• To be assembled thusly:

SELECT f.secret_fragment
FROM   fragment_sort_bin fs
JOIN   banner_fragment   f  ON (fs.frag_id    = f.frag_id)
JOIN   sort_bin          s1 ON (fs.sort_key_1 = s1.sort_key)
JOIN   sort_bin          s2 ON (fs.sort_key_2 = s2.sort_key)
JOIN   sort_bin          s3 ON (fs.sort_key_3 = s3.sort_key)
ORDER BY s1.bin, s2.bin, s3.bin;

• Sample solution