Very interesting. I'm liking this immensely, so I'd like to ask some questions despite knowing they won't make me look smart:

Your query returns the count for every possible cgroup x pclass combination every time. That's 70 x 12,000 = 840,000 count results returned. Then what - in Perl take just the combinations I'm intereted in. No - maybe I can add to your query - since a report uses just 5 industry_groups, I'd add: 

SELECT CG.answer as cgroup, CP.answer as pclass, count(*) FROM CG, CP
WHERE CG.company = CP.company AND (cgroup='a' OR ..... cgroup='e') GRO
+UP BY cgroup, pclass;

[download]
Which will reduce results significantly.

But - a single query on 15-million rows that returns ~50,000 results, faster than 350 queries on pairs of little ~10k~1k-row tables.....sounds possible.

In reply to Re^6: Feasability of quick generation of complex report from large db? by punch_card_don
in thread Feasability of quick generation of complex report from large db? by punch_card_don

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