Question

Considering the tables below, what is the best way to only return the team membership and its related player, but only one player from each team? The important part to note is that selection needs to be based on a given set of player ids. That is the starting point.

Using the example below I would have the player ids: 1,2,3 (among others) and what I need to end up with is the unique memberships from a list of user ids(1,2,3 in this case). I would want to end up with team_memberships with id 1 & 2

Thanks!

player
id | name
1  | bob
2  | joe
3  | tom

team_memberships
id | team_id | player_id
1  | 1       | 1
2  | 2       | 2
3  | 1       | 3

team
id | name
1  | jets
2  | kings

Answer 1

Do you mean

Select team_id, Min(player_id)
From team_Memberships
Where player_id In (1,2,3)
Group By team_id

If the player selected needs to be based on some other attribute in the players table, then:

Select team_id, 
   (Select Min(player_id) -- in case more than one player satisfies criterion
    From players 
    where playerId = m.Player_Id
       And [Some other ctiterion]) playerId
From team_Memberships m
Where player_id In (1,2,3)  
Group By team_id