Hey Guys! sorry for my english but I hope you  understand and could help me. I want to get the following information:   The time betweeen the timestamps "e"  in seconds from one object with an unique "ipid". Please see my attachement.   I tried with DATADIFF and LAG: SELECT DATEDIFF (second, ptime, e), q.* FROM (SELECT *, LAG(e) OVER (PARTITION BY ipid ORDER BY e) ptime FROM Table ) q WHERE ptime IS NOT NULL But: "The LAG function is not supported in PROC SQL, it is only valid within the DATA step."   You have any other idea?   Thanks!!! ... View more