From: | Mike Orr <sluggoster(at)gmail(dot)com> |
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To: | pgsql-general(at)postgresql(dot)org |
Subject: | Complex query question |
Date: | 2011-09-06 22:03:25 |
Message-ID: | CAH9f=uo+hF+FkGbu9Nta3Z_Q=Jrx8L68ryj6UT7uAeBKVxac+w@mail.gmail.com |
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Lists: | pgsql-general |
I have a complex query question whose answer I think would help me to
understand subselects and aggregates better. I have a table with four
columns of interest:
id (int primary key), loc_title (varchar null), loc_value (float
null), loc_unit (varchar null)
I want the output columns to be:
(1) each distinct value of loc_title, sorted
(2) an id of a record containing that loc_title
(3) the loc_value for the record in column 2
(4) the loc_unit for the record in column 2
I don't care as much how the records for columns 2-4 are chosen. It
could be max(loc_value), min(id), or something else. I just need some
sample records to test my program against.
Is this something I should be able to do with a single query with a
subselect, or is it too much for one query? I tried a few ways and
none of them were syntactically valid.
--
Mike Orr <sluggoster(at)gmail(dot)com>
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