SQL query to map year and month data

Want to write SQL query on below sample data.

id company yr   Jan      Feb          Mar      Apr
1   1      17   0.00     0.00         98.80    10.10
2   1      18   -143.60  90.60        -102.90  20.20
3   1      22   0.00     -10.20	      -60.80   -30.30
4   2      23   50.90    -100.00       4.64    -40.40

If value in month column is positive then input in CREDITAMOUNT field. If the value is negative then input in DEBITAMOUNT by removing (-) from front. Add month and year in the month column as shown in the expected output.

Expected result:

CREDITAMOUNT   DEBITAMOUNT   MONTH
0.00	       0.00          Jan2017
0.00	       143.60        Jan2018
0.00           0.00          Jan2022
50.90          0.00 	     Jan2023
0.00           0.00          Feb2017
90.60          0.00 	     Feb2018
0.00           10.20         Feb2022 
0.00           100.20        Feb2023
98.80          0.00          Mar2017
0.00           102.90 	     Mar2018
0.00           60.80         Mar2022 
4.64           0.00          Mar2023
10.10          0.00          Apr2017
20.20          0.00 	     Apr2018
0.00           30.30         Apr2022 
0.00           40.40         Apr2023

Something like this perhaps:

select id ,company ,yr, cast(Jan as numeric(19,2)) as Jan, cast(Feb as numeric(19,2)) as Feb, cast(Mar as numeric(19,2)) as Mar, cast(Apr as numeric(19,2)) as Apr
into #data
from 
(
	VALUES	(1,1,17,0.00    , 0.00      ,   98.80   , 10.10)
	,	(2,1,18,-143.60  ,90.60     ,   -102.90 , 20.20)
	,	(3,1,22,0.00     ,-10.20    ,   -60.80  , -30.30)
	,	(4,2,23,50.90    ,-100.00   ,    4.64   , -40.40)
) t (id ,company ,yr, Jan, Feb, Mar, Apr)

select	case when val < 0 then 0 else val end
,	case when val > 0 then 0 else -val end
, x.yr
from #data
CROSS APPLY (
	VALUES	(Jan, concat('Jan20', yr),1)
	,	(Feb, concat('Feb20', yr),2)
	,	(Mar, concat('Mar20', yr),3)
	,	(Apr, concat('Apr20', yr),4)
	) x (val, yr,sort)
order by sort, x.yr

-- Unpivot version:
select	case when val < 0 then 0 else val end
,	case when val > 0 then 0 else -val end
,	concat(mon, yr)
from	#data
unpivot (val for mon in (Jan, Feb,Mar,Apr)) upv 

drop table #data

I prefer to use the VALUES cross apply for UNPIVOTing, cause it's a bit more terse

EDIT: Added an UNPIVOT example as well

You can use unpivot :

WITH CTE AS (
  SELECT company, MONTH + cast(yr as varchar(2)) AS [MONTH], amount
  FROM mytable  
  UNPIVOT  
   (amount FOR MONTH IN   
      (Jan, Feb, Mar, Apr)  
  ) AS unpvt
)
SELECT company, MONTH, CASE WHEN amount >= 0 then amount else 0 end as  CREDITAMOUNT,
                       CASE WHEN amount < 0 then abs(amount) else 0 end as  DEBITAMOUNT 
FROM CTE

Demo here

Try this:

SELECT
  CASE
    WHEN Jan >= 0 THEN Jan
    ELSE 0
  END AS CREDITAMOUNT,
  CASE
    WHEN Jan < 0 THEN ABS(Jan)
    ELSE 0
  END AS DEBITAMOUNT,
  CONCAT('Jan', yr) AS MONTH
FROM table_name
UNION ALL
SELECT
  CASE
    WHEN Feb >= 0 THEN Feb
    ELSE 0
  END AS CREDITAMOUNT,
  CASE
    WHEN Feb < 0 THEN ABS(Feb)
    ELSE 0
  END AS DEBITAMOUNT,
  CONCAT('Feb', yr) AS MONTH
FROM table_name
UNION ALL
SELECT
  CASE
    WHEN Mar >= 0 THEN Mar
    ELSE 0
  END AS CREDITAMOUNT,
  CASE
    WHEN Mar < 0 THEN ABS(Mar)
    ELSE 0
  END AS DEBITAMOUNT,
  CONCAT('Mar', yr) AS MONTH
FROM table_name
UNION ALL
SELECT
  CASE
    WHEN Apr >= 0 THEN Apr
    ELSE 0
  END AS CREDITAMOUNT,
  CASE
    WHEN Apr < 0 THEN ABS(Apr)
    ELSE 0
  END AS DEBITAMOUNT,
  CONCAT('Apr', yr) AS MONTH
FROM table_name;