mmcclaf at gmail.com
Thu Feb 26 05:02:23 EST 2009
It is, however I was able to get the first 8 done, I am struggling with
these 3 particular ones. I have to make an SQL file based off of it, so this
seems to be a blockage in my works.
From: Gary Herron [mailto:gherron at islandtraining.com]
Sent: Thursday, February 26, 2009 1:46 AM
To: mmcclaf; python-list at python.org
Subject: Re: Queries
> I have to make some queries for 4 tables I have. The following
> relations are:
> Classes(class, type, country, numGuns, bore, displacement)
> Ships (name, class, launched)
> Battles (name, date)
> Outcomes (ship, battle, result)
> The three queries I'm stuck on are the following:
> 1. Find the classes that have only one ship as a member of that class
> (not all ships are listed in the Ship table)
> 2. Find the countries that had both battleships and battlecruisers
> (those fall under type in Classes)
> 3. Find those ships that "lived to fight another day"; they were
> damaged in one battle, but later fought in another.
> The best way for me to understand would be relational algebra for each
> of the statements.
Sounds like a homework assignment. Good luck with it.
> Any help in this would be greatly appreciated.
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