How can I select adjacent rows to an arbitrary row (in sql or postgresql)?

Question

I want to select some rows based on certain criteria, and then take one entry from that set and the 5 rows before it and after it.

Now, I can do this numerically if ther

Answer 1

You could do this utilizing row_number() (available as of 8.4). This may not be the correct syntax (not familiar with postgresql), but hopefully the idea will be illustrated:

SELECT *
FROM (SELECT ROW_NUMBER() OVER (ORDER BY primary_key) AS r, *
      FROM table
      WHERE active=1) t
WHERE 25 < r and r < 35

This will generate a first column having sequential numbers. You can use this to identify the single row and the rows above and below it.