You can achieve this with a self join. The idea is that you build a subselect that gives you the minimum value for each id, and then join that to the original table by id.

SELECT a.id, a.value-b.min_value FROM "table" a INNER JOIN (SELECT id, MIN(value) AS min_value FROM "table" GROUP BY id) AS b ON a.id = b.id;

I've posted this on Stackoverflow.

Thanks for the heads up,

Percy