How to find login times greater than 24 hours from custom table.

Question

Hello Guru's,
I am having trouble approaching how to construct a query that will find who has been logged in for more than 24 hours, this table is updated every few hours to show who's logged in and where- I am attempting to find out if someone has been logged in for more than 24 hours- if so, who and where. This is difficult for me because I need to compare each recorded for each user login and then see if the next entry is greater than 24 hours from the previous entry.
A table holds the login times and locations as table position_hist:
position_id,userid,upd_date.
Something like;
select position_id,userid,upd_date from position_hist where (select upd_date from position_hist where "the next entry for that user and that position is greater than 24 hours?????"
I guess the easier way to look at it is for a given position_id who has been logged in for more than 24 hours in one go.
Any advice would be brilliant :-)

Answer 1

It's hard without knowing your Oracle version, or having any sample data to work with. Please post that in the future using \ tags and DDL/DML.
Here is what I came up with as a guess:SQL> WITH POSITION_HIST AS
2 (
3 SELECT 1 AS POSITION_ID, 1 AS USER_ID, TRUNC(SYSDATE) AS UPD_DATE FROM DUAL UNION ALL
4 SELECT 1 AS POSITION_ID, 1 AS USER_ID, TRUNC(SYSDATE)+1 AS UPD_DATE FROM DUAL UNION ALL
5 SELECT 1 AS POSITION_ID, 1 AS USER_ID, TRUNC(SYSDATE)+2 AS UPD_DATE FROM DUAL UNION ALL
6 SELECT 1 AS POSITION_ID, 1 AS USER_ID, TRUNC(SYSDATE)+4 AS UPD_DATE FROM DUAL UNION ALL
7 SELECT 3 AS POSITION_ID, 2 AS USER_ID, TRUNC(SYSDATE) AS UPD_DATE FROM DUAL UNION ALL
8 SELECT 3 AS POSITION_ID, 2 AS USER_ID, TRUNC(SYSDATE)+1 AS UPD_DATE FROM DUAL UNION ALL
9 SELECT 3 AS POSITION_ID, 2 AS USER_ID, TRUNC(SYSDATE)+2 AS UPD_DATE FROM DUAL UNION ALL
10 SELECT 4 AS POSITION_ID, 21 AS USER_ID, TRUNC(SYSDATE)+2 AS UPD_DATE FROM DUAL
11 )
12 SELECT POSITION_ID
13 , USER_ID
14 FROM
15 (
16 SELECT POSITION_ID
17 , USER_ID
18 , UPD_DATE - LAG(UPD_DATE) OVER (PARTITION BY USER_ID ORDER BY UPD_DATE) AS LOGGED_IN_TIME
19 , ROW_NUMBER() OVER (PARTITION BY USER_ID ORDER BY UPD_DATE DESC) RN
20 FROM POSITION_HIST
21 )
22 WHERE LOGGED_IN_TIME > 1 AND RN = 1
23 /
POSITION_ID USER_ID
1 1