Opinons/Philosophy on adding flags to table to reduce queries?

What is the conventional wisdom regarding adding a boolean column to a table that is simply the result of a test on the values in about 6 other columns?

I'm dealing with large tables and my query currently involves conditions on the values of these 6 columns. I index all of these columns, but it seems like it would be much faster to simply look at a single boolean value. Probably about 80% of the rows in the table pass the boolean test.

The data in this table is fixed so I don't have to worry about an update affecting theboolean.

Would only a purist avoid something like this? Are there considerations here I'm missing?

Thanks.

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Jeff Wilson
jwilson2000_at_home.com
Eugene, Oregon

(541) 684-8590