Ranking teams equal on points in a pool based on who won the game they played

Question

I\'m writing an application that calculates the ranking of teams in the pool stages of a rugby competition (Rugby World Cup 2015, but it could apply to many other pool-based

Answer 1

This is complicated, but I would try the following.

1. Make a view each combination of opponents and who wins the tie.
2. With the results of your current ranking add in a column for the prior player, a column for prior rank, a column for next rank using windowing functions
3. Join to the view in step 1
4. Make a case statement that only sets a value if prior rank or next rank is equal that has the value from the view in step 1.
5. Sort by rank and the column in step 4

Answer 2

This need sql 2012+ using LEAD() and LAG() functions, Also require only two team have same Rank at this moment.

SCHEMA

CREATE TABLE Table1
    ([team] varchar(1), [rank] int);

INSERT INTO Table1
    ([team], [rank])
VALUES
    ('A', 1),('B', 1),('C', 2);

CREATE TABLE Table2
    ([team1] varchar(1), [team2] varchar(1), [win] varchar(1));

INSERT INTO Table2
    ([team1], [team2], [win])
VALUES
    ('A', 'B', 'B'), ('C', 'A', 'A'),('C', 'B', 'B');

SQL Fiddle Demo

WITH breakTie AS ( 
    SELECT
        [team],
        [rank],
        LAG([team]) OVER (ORDER BY [rank]) PreviousTeam,
        LEAD([team]) OVER (ORDER BY [rank]) NextTeam,
        LAG([rank]) OVER (ORDER BY [rank]) PreviousRank,
        LEAD([rank]) OVER (ORDER BY [rank]) NextRank
    FROM Table1
)
SELECT *, CASE 
       WHEN B.[rank] = B.[NextRank] and B.[team] = T.[win] THEN 1
       WHEN B.[rank] = B.[PreviousRank] and B.[team] = T.[win] THEN 1
       ELSE 0
    END as breakT
FROM breakTie B
LEFT JOIN Table2 T
   ON ( B.team = T.team1 or B.team = T.team2)
  AND ( B.NextTeam = T.team1 or B.NextTeam = T.team2)
ORDER BY 
    [rank],
    CASE 
       WHEN B.[rank] = B.[NextRank] and B.[team] = T.[win] THEN 1
       WHEN B.[rank] = B.[PreviousRank] and B.[team] = T.[win] THEN 1
       ELSE 0
    END

Answer 3

I want to add some other suggestion. Because your current problem have some contradictions and may not have a proper answer with current rules.

• First picture 4 team tie in same rank. If you use the information of the first 4 rows. You get a positions D, A, B, C but then last two can't be enforce.
  • In NFL they have some tie break called inside conference win. So you could count how many win each team have inside this group as a way of order.
  • So now all condition are pair comparasion.
  • In this case A and D have more wins and D beat A.
  • Now C beat B and A beat C. And you have a real order.
• But as show in picture 2 you can have everyone tie with 2 win.

My guess is you should analyze the restrictions. Maybe the order of rules is different and you can reduce THIS problem to one where only two team are tie.