Oracle Query to get single result depending on values in result set - sql

Question

WITH T1 AS SELECT DISTINCT(DETAILS) FROM ( SELECT STATUS, PREREQUISITE_NM,
(case when (STATUS='Completed' ) then 'Completed'
when (STATUS='Pending' ) then 'Pending'
when (STATUS='Failed' and PREREQUISITE_NM = 'Y') then 'Failed'
when (STATUS='Failed' and PREREQUISITE_NM = 'N') then 'Completed'
end )DETAILS FROM TABLE_LIST WHERE ID=1))
T2 AS ( SELECT DETAILS FROM T1)
Result 1 :
Pending
Failed
Completed.
Result 2:
Failed
Completed.
In above Query we see the different result set as per data available. I want to write a query in T2 Block which should give Output as :
for Pending/Failed/Completed : should give Pending as output.
For Failed/Completed : should give Failed as Output.
Is it possible to achieve this through query without using PL SQL block. like using WITH clause?
I can explain my aim such as
Lets say T1 Block is giving me result as three rows Pending,Failed, Completed then I want Pending as a Output value. If T1 Block is giving me result as Failed, Completed then I want to Failed as Output value. If T1 block is giving only Completed then Completed will be considered as a output value.

Answer 1

Thanks Roberto and Barbaros Ozhan, Both Answers were useful.Posting another way shared by one of my colleague.
WITH T1 AS (
SELECT
DISTINCT(DETAILS)
FROM (
SELECT STATUS, PREREQUISITE_NM,
(
CASE
WHEN (STATUS = 'Failed' ) THEN
CASE WHEN PREREQUISITE_NM = 'Y' THEN 'Failed'
WHEN PREREQUISITE_NM = 'N' THEN 'Completed'
END
ELSE
STATUS
END
)DETAILS FROM TABLE_lIST WHERE ID=1)
),
T2 AS
(
SELECT CASE
WHEN EXISTS
( SELECT DETAILS FROM T1 where DETAILS='Pending' )
THEN 'Pending'
WHEN EXISTS
( SELECT DETAILS FROM T1 WHERE DETAILS='InProgress' )
THEN 'InProgress'
WHEN EXISTS
(SELECT DETAILS FROM T1 where DETAILS='Failed' )
THEN 'Failed'
ELSE 'Completed' END as DETAILS from DUAL
)SELECT * FROM T2

Answer 2

You can use ROW_NUMBER() Analytic function to bring those status values in alphabetical order descendingly which would suite your need :
WITH T1 AS
(
SELECT DISTINCT (CASE
WHEN (STATUS = 'Failed' ) THEN
CASE WHEN PREREQUISITE_NM = 'Y' THEN 'Failed'
WHEN PREREQUISITE_NM = 'N' THEN 'Completed'
END
ELSE
STATUS
END) AS details
FROM TABLE_LIST
WHERE ID = 1
), T2 AS
(
SELECT T1.*, ROW_NUMBER() OVER (ORDER BY details DESC) AS rn
FROM T1
)
SELECT details
FROM T2
WHERE rn = 1

Answer 3

After reading your comments, I came up with this solution, that perhaps is not the best, but at the end gives the output you expect , based on that what you actually want is to transpose the rows produced in t1 to columns in t2
I used my own test, please be aware to replace the columns or modify whatever is necessary to adapt it to your own query
SQL> desc my_test
Name Null? Type
----------------------------------------- -------- ----------------------------
C1 NUMBER
C2 VARCHAR2(20)
C3 VARCHAR2(1)
SQL> select * from my_test ;
C1 C2 C3
---------- -------------------- -
1 Failed Y
2 Completed Y
1 Pending Y
1 Pending N
SQL>
So, If just got the first part of my query
SQL> WITH T1 AS (
SELECT DISTINCT c2 FROM ( SELECT c1,c2,
case when c2='Completed' then 'Completed'
when c2='Pending' then 'Pending'
when c2='Failed' and c3 = 'Y' then 'Failed'
when c2='Failed' and c3 = 'N' then 'Completed'
else c2
end FROM my_test WHERE c1=1
) )
select trim ( completed || ' ' || failed || ' ' || pending ) as result
from
(
select * from t1 pivot ( max(c2) for c2 in ( 'Completed' as Completed, 'Failed' as Failed, 'Pending' as Pending ) )
)
/ 9 10 11 12 13 14 15
RESULT
--------------------------------------------------------------
Failed Pending
Now I only need to build a case over that result ( modify it to your own requirements )
SQL> WITH T1 AS (
SELECT DISTINCT c2 FROM ( SELECT c1,c2,
case when c2='Completed' then 'Completed'
when c2='Pending' then 'Pending'
when c2='Failed' and c3 = 'Y' then 'Failed'
when c2='Failed' and c3 = 'N' then 'Completed'
else c2
end FROM my_test WHERE c1=1
) )
select
case when result = 'Completed Failed Pending' then 'Pending'
when result = 'Completed Failed' then 'Failed'
when result = 'Failed Pending' then 'Failed' -- I guess
when result = 'Completed Pending' then 'Pending' -- I guess
end as output
from (
select trim ( completed || ' ' || failed || ' ' || pending ) as result
from
(
select * from t1 pivot ( max(c2) for c2 in ( 'Completed' as Completed, 'Failed' as Failed, 'Pending' as Pending ) )
)
)
/
OUTPUT
-------
Failed
SQL>