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Date: Thu, 27 Jun 2002 14:47:38 -0700
From: Vernon Wu <vernonw@gatewaytech.com>
Subject: Two-way query
To: pgsql-sql@postgresql.org
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I need help to find an effective method to resolve a two-way query problem. 

Problem:
One is looking for friends who meet his criteria while people will not show up in his friend list if this person's criteria don't 
meet their criteria.

His criteria:
age: 24 ? 32
education: at least with a bachelor degree
occupation: programmer

DB tables:

profile:	id | age | education | occupation

preference:	id | age range | education set | occupation set

Search:

Batch of sql statements:
1.fetch this person's preference (select criteria)
2.Use his preference issue a query statement as:
select id from profile where (age < 33 and age > 23) and (education='bachelor' or education='master' or 
education='phd') and (occupation='programmer')
3.fetch preference with ids from the previous query.
4.Issue a similar query of the step 2 to find out whether he is qualified to be a friend of people in step 2

What is the most effective sql statement for this problem?


Thank in advance for your advice.

Vernon