Conditional Analytic Function - sql

Question

Work:
,MAX(CASE WHEN MAX(HIST)
AND workid IS NOT NULL
AND ROLE = 'red'
THEN 'ASSIGNED'
ELSE 'UNASSIGNED'
END)
OVER (PARTITION BY id) AS ASSIGNED
Criteria:
Partition By ID
Look at last entry from each ID, utilizing the PKHistid column
If Role = Red and Workid IS NOT NULL from the last entry for each ID
Then Assigned
Else Unassigned
Table:
PKHistid ID Role Entry_Date Workid
1 101 Red 1/1/17 201
2 101 Yellow 1/2/17 201
3 102 Yellow 5/1/17 (Null)
4 102 Red 6/1/17 202
5 103 Red 7/1/17 202
6 103 Red 7/5/17 202
Expected Results: (New Column Assigned_Status)
PKHistid ID Role Entry_Date Workid *Assigned_Status
1 101 Red 1/1/17 201 Unassigned
2 101 Yellow 1/2/17 201 Unassigned
3 102 Yellow 5/1/17 (Null) Assigned
4 102 Red 6/1/17 202 Assigned
5 103 Red 7/1/17 202 Assigned
6 103 Red 7/5/17 202 Assigned

Answer 1

Is this "instead of" your earlier question (also posted today), or is it "in addition to" it? If it is "in addition to", note that you can do both things in the same query.
Here you need a case expression to create the additional column. In the case expression, the condition uses an analytic function. I prefer the analytic version of the LAST function (which, unfortunately, many developers don't seem to know and use). Please read the Oracle documentation for it if it is not familiar to you.
Note that analytic functions can't be nested; but there is absolutely no prohibition against using analytic functions in case expressions. I often see solutions where the analytic function is called in a subquery, and then further processing (such as case expressions using the result from the analytic functions) is done in an outer query. Unnecessary layering!
with
inputs ( pkhistid, id, role, entry_date, workid) as (
select 1, 101, 'Red' , to_date('1/1/17', 'mm/dd/rr'), 201 from dual union all
select 2, 101, 'Yellow', to_date('1/2/17', 'mm/dd/rr'), 201 from dual union all
select 3, 102, 'Yellow', to_date('5/1/17', 'mm/dd/rr'), null from dual union all
select 4, 102, 'Red' , to_date('6/1/17', 'mm/dd/rr'), 202 from dual union all
select 5, 103, 'Red' , to_date('7/1/17', 'mm/dd/rr'), 202 from dual union all
select 6, 103, 'Red' , to_date('7/5/17', 'mm/dd/rr'), 202 from dual
)
-- End of simulated inputs (for testing only, not part of the solution).
-- SQL query begins BELOW THIS LINE. Use your actual table and column names.
select pkhistid, id, role, entry_date, workid,
case when max(role) keep (dense_rank last order by pkhistid)
over (partition by id) = 'Red'
and
max(workid) keep (dense_rank last order by pkhistid)
over (partition by id) is not null
then 'Assigned'
else 'Unassigned' end as assigned_status
from inputs
order by id, pkhistid -- If needed
;
PKHISTID ID ROLE ENTRY_DATE WORKID ASSIGNED_STATUS
---------- ---------- ------ ---------- ---------- ---------------
1 101 Red 01/01/17 201 Unassigned
2 101 Yellow 01/02/17 201 Unassigned
3 102 Yellow 05/01/17 Assigned
4 102 Red 06/01/17 202 Assigned
5 103 Red 07/01/17 202 Assigned
6 103 Red 07/05/17 202 Assigned