SQL on Self Table Join - sql

Question

I am trying to do a simple self-join SQL and a join to a 2nd table and for the life of me I can't figure it out. I've done some research and can't seem to glean the answer from similar questions. This query is for MS-Access running in VB.NET.
I have 2 tables:
TodaysTeams
-----------
TeamNum PlayerName PlayerID
------- ---------- --------
1 Mark 100
1 Brian 101
2 Mike 102
2 Mike 102
(Note the last 2 rows above are not a typo. In this case a player can be paired with themselves to form a team)
TodaysTeamsPoints
-----------------
TeamNum Points
------- ------
1 90
2 85
The result I want is (2 rows, 1 for each team):
TeamNum PlayerName1 PlayerName2 Points
------- ----------- ----------- ------
1 Mark Brian 90
2 Mike Mike 85
Here is my SQL:
SELECT DISTINCT A.TeamNum, A.PlayerName as PlayerName1, B.PlayerName AS PlayerName2, C.Points
FROM ((TodaysTeams A INNER JOIN
TodaysTeamsPoints C ON A.TeamNum = C.TeamNum) INNER JOIN
TodaysTeams B ON A.TeamNum = B.TeamNum)
ORDER BY C.Points DESC
I know I am missing another join as I'm returning a cartesian produce (i.e. too many rows).
I would appreciate help as to what I am missing here.
Thank you.

Answer 1

Whilst Gordon's suggested method will work well providing that there are at most two players per team, the method breaks down if ever you add another team member and wish to display them in a separate column.
The difficulty in displaying the data in a manner that you can describe logically but cannot easily produce using a query usually implies that the database structure is sub optimal.
For your particular setup, I would personally recommend the following structure:
+---------------+ +----------+------------+
| Players | | PlayerID | PlayerName |
+---------------+ +----------+------------+
| PlayerID (PK) | | 100 | Mark |
| PlayerName | | 101 | Brian |
+---------------+ | 102 | Mike |
+----------+------------+
+-------------+ +--------+----------+
| Teams | | TeamID | TeamName |
+-------------+ +--------+----------+
| TeamID (PK) | | 1 | Team1 |
| TeamName | | 2 | Team2 |
+-------------+ +--------+----------+
+-------------------+ +--------+--------------+----------+
| TeamPlayers | | TeamID | TeamPlayerID | PlayerID |
+-------------------+ +--------+--------------+----------+
| TeamID (PK) | | 1 | 1 | 100 |
| TeamPlayerID (PK) | | 1 | 2 | 101 |
| PlayerID (FK) | | 2 | 1 | 102 |
+-------------------+ | 2 | 2 | 102 |
+--------+--------------+----------+
Using this method, you can use condition aggregation or a crosstab query pivoting on the TeamPlayerID to produce each of your columns, and you would not be limited to two columns.

Answer 2

You can use aggregation:
SELECT ttp.TeamNum, MIN(tt.PlayerName) as PlayerName1,
MAX(tt.PlayerName) as PlayerName2,
ttp.Points
FROM TodaysTeamsPoints as ttp INNER JOIN
TodaysTeams as tt
ON tt.TeamNum = ttp.TeamNum
GROUP BY ttp.TeamNum, ttp.Points
ORDER BY ttp.Points DESC;