Question

I have this table:

Team | Player
Barca | Messi
Chelsea | Lampard
Barca | Messi
Barca | Messi
Chelsea | Lampard
Chelsea | Drogba
Barca | Iniesta
Barca | Xavi
Barca | Iniesta
Barca | Puyol

So I need a query that retrieves the top two common players in each team. something like this:

Team | Player
Barca | Messi
Barca | Iniesta
Chelsea | Lampard
Chelsea | Drogba

Answer 1

You can use a subquery/CTE to calculate the counts of each player and the ranking, by numbering rows according to descending order of count per team. Then pull out the top two players from each team:

Query (demo):

with ranks as (
  select
    team, player, count(*) as count,
    row_number() over (partition by team order by count(*) desc) as teamrank
  from players p
  group by team, player
)
select
  team, player
from
  ranks
where teamrank <= 2
order by team, teamrank

Results:

|    TEAM |  PLAYER |
---------------------
|   Barca |   Messi |
|   Barca | Iniesta |
| Chelsea | Lampard |
| Chelsea |  Drogba |