Postgres 11

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CREATE TABLE tab
AS
SELECT '01/01/2017'::date AS "date",    10 AS col1,      10 AS col2,     20 AS col3
UNION ALL SELECT '02/01/2017',    10 ,      10  ,    20
UNION ALL SELECT '03/01/2017',    10,       10 ,     20
UNION ALL SELECT '04/01/2017',    10 ,      10 ,     20
UNION ALL SELECT '05/01/2017',    10  ,     10 ,     20
UNION ALL SELECT '06/01/2017',  10   ,    10   ,   20
6 rows affected

SELECT "date",col1,col2,col3, closing-col1-col2-col3 AS opening, closing
FROM (SELECT *, SUM(col1+col2+col3) OVER(ORDER BY "date") AS closing
      FROM tab) sub


date
col1
col2
col3
opening
closing


2017-01-01
10
10
20
0
40

2017-01-02
10
10
20
40
80

2017-01-03
10
10
20
80
120

2017-01-04
10
10
20
120
160

2017-01-05
10
10
20
160
200

2017-01-06
10
10
20
200
240


SELECT tab.*,SUM(x) OVER(ORDER BY "date")-s.x AS opening,SUM(x) OVER(ORDER BY "date") AS closing
FROM tab,LATERAL(SELECT col1+col2+col3) AS s(x)


date
col1
col2
col3
opening
closing


2017-01-01
10
10
20
0
40

2017-01-02
10
10
20
40
80

2017-01-03
10
10
20
80
120

2017-01-04
10
10
20
120
160

2017-01-05
10
10
20
160
200

2017-01-06
10
10
20
200
240

date	col1	col2	col3	opening	closing
2017-01-01	10	10	20	0	40
2017-01-02	10	10	20	40	80
2017-01-03	10	10	20	80	120
2017-01-04	10	10	20	120	160
2017-01-05	10	10	20	160	200
2017-01-06	10	10	20	200	240