SQL max and min dates with filter

Question

The following account closed on 1/19/2018, then reopened on 2/27/2018, then closed again on 3/26/2018. How do I write the sql to capture when this account was opened and closed. The closerestrictind = 'C' is when the account was closed.

We are working in a data warehouse where the data is loaded everyday to capture all the history.

It should look like this for acct 1234:

closed on 1/19/2018
re-opened on 2/27/2018
closed on 3/26/2018

Thank you!

Answer 1

You can use lag() :

select acctnbr, effectivedate,
       (case when closerestrictedind = 'C' then 'closed' else 'opened' end) as action
from (select t.*, lag(closerestrictedind) over (partition by acctnbr order by effectivedate) as prev_cr
      from t
     ) t
where prev_cr <> closerestrictedind;

Answer 2

You can do two select statements, the first one with row_number() partition by acctnbr, order by date... save it in tmp table

The second select, inner join this table with itself, t1 and t2.

Where t1.closerestrictedind = 'C'

And the join where t1.rownum > t2.rownum +1