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Re: Struggling with qualifiers involving sets
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Re: Struggling with qualifiers involving sets


  • Subject: Re: Struggling with qualifiers involving sets
  • From: Denis Stanton <email@hidden>
  • Date: Tue, 5 Aug 2003 09:20:13 +1200

On Tuesday, August 5, 2003, at 03:06  AM, Jonathan Rochkind wrote:

It may not be a major pain, but it's not quite the same thing. It takes two trips to the db, and depending on your db and how it functions, it might end up being a lot slower than the one-query version. For a database with a large population, where the subquery returns thousands of rows, the two-query version might not even work----some databases have a maximum number of terms you can have in the "WHERE" clause.

Since I started this particular thread with a real-world requirement, I'll just comment that in my case the number of items in the match set is typically 1, sometimes 2 and has a maximum of about 8. At this level I am well served by the EOOrQualifier code suggested by George.


The requirement I am dealing with is similar to "find all the movies in my selected genres" where the movie genres are selected by checking a row of boxes. (I'm not actually dealing with movies, but that example is easier to define)

I appreciate the thought that has gone into discussing the possible solutions.

Denis Stanton
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