Postgres 13

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CREATE TABLE mytable (
    number int,
    name text,
    avg_result numeric[][]
);

INSERT INTO mytable VALUES
(1, 'Kevin', '{{2.0,10},{3.0,50}}'),
(2, 'Max', '{{1.0,10},{4.0,30},{5.0,20}}');

SELECT * FROM mytable

CREATE TABLE



INSERT 0 2




number
name
avg_result


1
Kevin
{{2.0,10},{3.0,50}}

2
Max
{{1.0,10},{4.0,30},{5.0,20}}



SELECT 2


SELECT
    *
FROM mytable,
    unnest(avg_result) WITH ORDINALITY as elements(value, idx)


number
name
avg_result
value
idx


1
Kevin
{{2.0,10},{3.0,50}}
2.0
1

1
Kevin
{{2.0,10},{3.0,50}}
10
2

1
Kevin
{{2.0,10},{3.0,50}}
3.0
3

1
Kevin
{{2.0,10},{3.0,50}}
50
4

2
Max
{{1.0,10},{4.0,30},{5.0,20}}
1.0
1

2
Max
{{1.0,10},{4.0,30},{5.0,20}}
10
2

2
Max
{{1.0,10},{4.0,30},{5.0,20}}
4.0
3

2
Max
{{1.0,10},{4.0,30},{5.0,20}}
30
4

2
Max
{{1.0,10},{4.0,30},{5.0,20}}
5.0
5

2
Max
{{1.0,10},{4.0,30},{5.0,20}}
20
6



SELECT 10


SELECT
    number,
    name,
    SUM(value) FILTER (WHERE idx % 2 = 1) / 2
FROM mytable,
    unnest(avg_result) WITH ORDINALITY as elements(value, idx)
GROUP BY number, name


number
name
?column?


2
Max
5.0000000000000000

1
Kevin
2.5000000000000000



SELECT 2

number	name	avg_result	value	idx
1	Kevin	{{2.0,10},{3.0,50}}	2.0	1
1	Kevin	{{2.0,10},{3.0,50}}	10	2
1	Kevin	{{2.0,10},{3.0,50}}	3.0	3
1	Kevin	{{2.0,10},{3.0,50}}	50	4
2	Max	{{1.0,10},{4.0,30},{5.0,20}}	1.0	1
2	Max	{{1.0,10},{4.0,30},{5.0,20}}	10	2
2	Max	{{1.0,10},{4.0,30},{5.0,20}}	4.0	3
2	Max	{{1.0,10},{4.0,30},{5.0,20}}	30	4
2	Max	{{1.0,10},{4.0,30},{5.0,20}}	5.0	5
2	Max	{{1.0,10},{4.0,30},{5.0,20}}	20	6