| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Thomas Kellerer <spam_eater(at)gmx(dot)net> |
| Cc: | pgsql-general(at)postgresql(dot)org, Merlin Moncure <mmoncure(at)gmail(dot)com> |
| Subject: | Re: sudoku in an sql statement |
| Date: | 2009-11-01 15:19:47 |
| Message-ID: | 6273.1257088787@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Thomas Kellerer <spam_eater(at)gmx(dot)net> writes:
> Merlin Moncure wrote on 31.10.2009 14:32:
>> an oracle guy wrote an sql statement that solves a sudoku
>> puzzle...using an oracle specific feature. Still, it's pretty neat,
>> and an absolute gem of lateral thinking.
>>
>> http://technology.amis.nl/blog/6404/oracle-rdbms-11gr2-solving-a-sudoku-using-recursive-subquery-factoring
> There is also a DB2 version:
> http://forums.devshed.com/db2-development-114/absolute-sudoku-solver-641065.html
The DB2 version looks amazingly brute-force :-(
I think the Oracle guy's version could easily be adapted to PG 8.4 ---
those little rownum subqueries seem to be just a substitute for not
having generate_series(1,9), and everything else is just string-pushing.
Don't have time to try it myself right now, though.
regards, tom lane
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