Re: Need to subtract values between previous and current row - Mailing list pgsql-sql

On fös, 2006-12-15 at 18:27 +0600, Partha Guha Roy wrote:
> Hi,
> 
> I have a table that contains data like this:
> 
> ID           ATIME (MM/dd/yyyy)
> ==          ====
> 1            10/12/2006
> 2            10/14/2006
> 3            10/18/2006
> 4            10/22/2006 
> 5            10/30/2006
> 
> Now I need a query that will subtract atime of row 1 from row 2, row2
> from row3  and so on...

if there are no missing IDs you can use a self join
SELECT t1.atime,t2,atime    FROM t AS t1         JOIN t AS t2 ON (t1.ID=t2.ID+1)


otherwise, you could use a loop in a pl/pgpsql function


gnari