Using a pl-sql procedure to select best team from players database

Question

I am using oracle SQL developer 11g. I have a database of 100 football players. I have a table called PROFILE_PLAYERS which has following columns:

player_id, player_name, attack_skill(number),
defense_skill(number), passing_skill(number), GK_skill(number)

Now, I want to form a team of 11 players which contains 3 best attackers (highest attack_skill), 4 best midfielders (highest passing_skill), 3 best defenders (best defense_skill) and 1 best GK (best GK_skill).

I want to write a procedure which displays the 11 best players with their player_name and player_id.

Can I use the rank() here? Should I use for loop with a counter in the procedure?

Answer 1

If you ignore that the same player could be selected more than once due to different skills, the query could look like this:

select player_id, player_name
from (
    select player_id, player_name,
        rank() over(order by attack_skill desc) attack_rank,
        rank() over(order by defense_skill desc) defense_rank,
        rank() over(order by passing_skill desc) passing_rank,
        rank() over(order by gk_skill desc) gk_rank
    from profile_players
)
where attack_rank <= 3 or defense_rank <= 4
   or passing_rank <= 3 or gk_rank <= 1;

To be sure that you get exactly 11 players, you have to apply a few tricks:

select player_id, player_name
from (
    select player_id, player_name,
        least((attack_rank - 1) / 3, (defense_rank - 1) / 4,
            (passing_rank - 1) / 3, gk_rank - 1) blended_rank
    from (
        select player_id, player_name,
            rank() over(order by attack_skill desc) attack_rank,
            rank() over(order by defense_skill desc) defense_rank,
            rank() over(order by passing_skill desc) passing_rank,
            rank() over(order by gk_skill desc) gk_rank
        from profile_players
    )
    order by blended_rank desc
)
where rownum <= 11;

You can then wrap this query into a stored procedure if you really need to have a procedure.