Question

HI
I am looking for some help I just can’t seem to get my head how self joins work. I have this sql code

select Persno'Name',convert(char(20), A_Date , 13)'Logins',acode 
from atrail as LOGIN 
where acode = 'LOGIN' OR acode = 'LOGOUT'
order by a_date desc

Which produces a list of User names and when the have logged in and out. What I am trying to acheive is to get anther column with the LOGOUT date next to the date they logged in date so that it is easyer to see when they logged in and out.

Thanks

Andy

Answer 1

This could be another way to achieve it:

SELECT Name, [LOGIN] as login_date, [LOGOUT] as logout_date
FROM
(
    SELECT Persno Name,convert(char(20), A_Date , 13) Logins, acode
    FROM atrail 
    WHERE acode = 'LOGIN' OR acode = 'LOGOUT'
    ORDER BY a_date DESC
) AS login_table
PIVOT
(
    MAX(Logins) FOR acode IN ([LOGIN],[LOGOUT])
) AS pvt_table
ORDER BY login_date DESC

This is considering that for each login date there is a logout date, and that for each person there is just one login and one logout row.