Postgres 9.5

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create table t (id int, price int, units int);
insert into t values
(1, 100,15),
(1, 90,10),
(1, 50,8),
(1, 40,8),
(1, 30,7),
(2, 110,22),
(2, 60,8),
(2, 50,11);
;

8 rows affected

SELECT *
FROM t


id
price
units


1
100
15

1
90
10

1
50
8

1
40
8

1
30
7

2
110
22

2
60
8

2
50
11


select id,
  ceil(avg(price)) as avg_price,
  percentile_cont(0.5) within group (order by price) as median_price,
  ceil( sum (price) / sum (units) ) AS avg_pp_unit,
  ceil( percentile_cont(0.5) within group (order by price)  / 
        percentile_cont(0.5) within group (order by units) ) as median_pp_unit
from t
group by id


id
avg_price
median_price
avg_pp_unit
median_pp_unit


1
62
50
6
7

2
74
60
5
6


select id,
ceil(avg(price)) as avg_price
,percentile_disc(0.5) within group (order by price) as median_price
,ceil( sum (price) / sum (units) ) AS avg_pp_unit
,ceil( percentile_disc(0.5) within group (order by price)  / 
        percentile_disc(0.5) within group (order by units) ) as median_pp_unit
from t
group by id


id
avg_price
median_price
avg_pp_unit
median_pp_unit


1
62
50
6
6

2
74
60
5
5