Complex SQL calculated/Group Query

Question

I am trying to write a complex aggregate query(s) to compile a standings table for a soccer league.
There are four related tables:
Matches
Goals
Players
teams
I have yet to finalize the database structure so I can add fields if necessary.
In the goals table I track the match that the goal was scored in and which player
scored it.
I am trying to create a query that will give me a standings table.
The fields I need to calculate are:
team name
Wins
Loses
Draws
For instance:  There was a match on 4/21/2012.  The players on HomeTeam(A) scored a combined 6 goals.  The players on AwayTeam(B) scored 1 goal (All stored in the Goals table).  Therefore, Hometeam won by a score of 6-1.  I need
a query that spits out:
Team                Wins          Losses          Draws         
Points
HomeTeam(A)      1                 0                 0                
3
AwayTeam(B)       0                 1                 0                 3
Wins are worth 3 Losses 0 and Draws 1 point each team.
I am a long time SQL admin, but I think the complexity of calculating this is a little beyong me.  I need some help to get where I need to be.

Answer 1

Okay, I haven't yet been able to figure out the draws because of the trouble of linking back to both teams, but here's what I have so far.
First, here is the test data:
Declare @tvMatches Table (
MatchID int IDENTITY(1,1)
,MatchDate datetime
,HomeTeamID int
,AwayTeamID int
Declare @tvGoals Table (
GoalID int IDENTITY(1,1)
,MatchID int
,PlayerID int
,TeamID int
Declare @tvPlayers Table (
PlayerID int IDENTITY(1,1)
,TeamID int
,PlayerName varchar(30)
Declare @tvTeams Table (
TeamID int IDENTITY(1,1)
,TeamName varchar(20)
Insert @tvTeams
Select 'Winners'
Union All
Select 'Losers'
Union All
Select 'Friars'
Union All
Select 'Planes'
Insert @tvPlayers
Select 1, 'Bill'
Union All
Select 1, 'Jim'
Union All
Select 1, 'Ken'
Union All
Select 2, 'James'
Union All
Select 2, 'Smithy'
Union All
Select 2, 'Flip'
Union All
Select 3, 'Dave'
Union All
Select 3, 'Alan'
Union All
Select 3, 'Ethan'
Union All
Select 4, 'Naomi'
Union All
Select 4, 'Erland'
Union All
Select 4, 'Alejandro'
Insert @tvMatches
Select '20120101', 1, 2
Union All
Select '20120201', 3, 4
Union All
Select '20120301', 4, 1
--Winners beat Losers 3-2
--Planes beat Friars 4-2
--Winners beat Planes 2-1
Insert @tvGoals --Match, Player, Team
Select 1, 1, 1
Union All
Select 1, 3, 1
Union All
Select 1, 5, 2
Union All
Select 1, 6, 2
Union All
Select 1, 2, 1
Union All
Select 2, 7, 3
Union All
Select 2, 8, 3
Union All
Select 2, 10, 4
Union All
Select 2, 11, 4
Union All
Select 2, 12, 4
Union All
Select 2, 11, 4
Union All
Select 3, 1, 1
Union All
Select 3, 3, 1
Union All
Select 3, 11, 4
Using this test data, you want to compile the actual match outcomes.  This can be problematic to do on the fly every time though, if you have a lot of matches or teams to calculate for.  But, with a simple cte, we have:
;with cteMatches as
Select m.MatchID
,m.MatchDate
,m.HomeTeamID
,ht.TeamName HomeTeamName
,m.AwayTeamID
,at.TeamName AwayTeamName
,( Select Count(1)
From @tvGoals g
Where g.MatchID = m.MatchID
And g.TeamID = m.HomeTeamID
) HomeScore
,( Select Count(1)
From @tvGoals g
Where g.MatchID = m.MatchID
And g.TeamID = m.AwayTeamID
) AwayScore
From @tvMatches m
join @tvTeams ht
on m.HomeTeamID = ht.TeamID
join @tvTeams at
on m.AwayTeamID = at.TeamID
) --select * from cteMatches
This returns the MatchID, MatchDate, team information and the score.  Basically, you have the match, team and player data tied to the goals table, so you just do a count (using correlated subqueries) to get the score of each team.  Next step is
to calculate the winner and loser (and eventually whether there even was a winner) by comparing the scores:
,cteWinners as
Select cm.MatchID
,cm.HomeTeamID
,cm.HomeTeamName
,cm.AwayTeamID
,cm.AwayTeamName
,Case
When cm.HomeScore > cm.AwayScore Then cm.HomeTeamID
When cm.HomeScore < cm.AwayScore Then cm.AwayTeamID
Else 0
End WinningTeamID
,Case
When cm.HomeScore > cm.AwayScore Then cm.AwayTeamID
When cm.HomeScore < cm.AwayScore Then cm.HomeTeamID
Else 0
End LosingTeamID
From cteMatches cm
) --select * from ctewinners
This returns MatchID, team information and the ID's for winning and losing teams.  For now it returns 0 if it's a draw.  Once we know the outcomes of all the matches, we calculate the actual win/loss for each team:
,cteRecords as
Select t.TeamName
,Count( Case
When cw.WinningTeamID = t.TeamID Then 1
End
) Wins
,Count( Case
When cw.LosingTeamID = t.TeamID Then 1
End
) Losses
From @tvTeams t
join cteWinners cw
on t.TeamID = cw.HomeTeamID
or t.TeamID = cw.AwayTeamID
Group By t.TeamName
) --select * from cteRecords
That last cte returns just team name, and then the number of wins and losses for each team.  This is where I got stuck with the draws, because I'm not quite sure yet how to properly assign a draw to both teams involved.
Now, finally you put it all together with some simple match to determine the points, and there you are:
Select TeamName
,Wins
,Losses
,(Wins * 3) Points
From cteRecords