Como codificar um determinado algoritmo matemático

CREATE TABLE League (
  LeagueID   INT PRIMARY KEY, 
  LeagueName VARCHAR(30) UNIQUE
);

CREATE TABLE Team (
  TeamID           INT PRIMARY KEY, 
  TeamAbbreviation CHAR(3) UNIQUE, 
  TeamName         VARCHAR(50) UNIQUE, 
  LeagueID         INT CONSTRAINT FK_Team_League REFERENCES League(LeagueID) 
);

CREATE TABLE Fixture (
  FixtureID   INT PRIMARY KEY,
  WeekNumber  INT NOT NULL,
  FixtureDate DATE NULL,
  HomeTeamID  INT NULL,
  AwayTeamID  INT NULL,
  LeagueID    INT CONSTRAINT FK_Fixture_League REFERENCES League(LeagueID)
);

INSERT INTO League VALUES ( 1, 'League 1' );
INSERT INTO League VALUES ( 2, 'League 2' );

INSERT INTO Team VALUES ( 1, 'AAA', 'Team A', 1 );
INSERT INTO Team VALUES ( 2, 'BBB', 'Team B', 1 );
INSERT INTO Team VALUES ( 3, 'CCC', 'Team C', 1 );
INSERT INTO Team VALUES ( 4, 'DDD', 'Team D', 1 );
INSERT INTO Team VALUES ( 5, 'EEE', 'Team E', 2 );
INSERT INTO Team VALUES ( 6, 'FFF', 'Team F', 2 );
INSERT INTO Team VALUES ( 7, 'GGG', 'Team G', 2 );
INSERT INTO Team VALUES ( 8, 'HHH', 'Team H', 2 );
INSERT INTO Team VALUES ( 9, 'III', 'Team I', 2 );

INSERT INTO Fixture
WITH league_teams ( id, leagueid, idx, is_fake, num_teams, num_fake ) AS (
  -- Generate a unique-per-league index for each team that is between 0
  -- and the (number of teams - 1) and calculate the number of teams
  -- and if this is an odd number then generate a fake team as well.
  SELECT TeamID,
         LeagueID,
         ROW_NUMBER() OVER ( PARTITION BY LeagueID ORDER BY TeamID ) - 1,
         0,
         COUNT(1) OVER ( PARTITION BY LeagueID ),
         MOD( COUNT(1) OVER ( PARTITION BY LeagueID ), 2 )
  FROM Team
  UNION ALL
  SELECT NULL,
         LeagueID,
         COUNT(1),
         1,
         COUNT(1),
         1
  FROM   Team
  GROUP BY LeagueID
  HAVING MOD( COUNT(1), 2 ) > 0
),
cte ( home_idx, away_idx, week_number, leagueID, num_teams, num_fake ) AS (
  -- Start by calculating the round 1 games
  SELECT idx,
         num_teams + num_fake - 1 - idx,
         1,
         LeagueID,
         num_teams,
         num_fake
  FROM   league_teams
  WHERE  2 * idx < num_teams
UNION ALL
  -- Then generate the successive rounds with the two cases when the
  -- away team has the maximum index or otherwise.
  SELECT CASE away_idx
           WHEN num_teams + num_fake - 1
           THEN home_idx + 1
           ELSE MOD( home_idx + 1, num_teams + num_fake -1 )
           END,
         CASE away_idx
           WHEN num_teams + num_fake - 1
           THEN away_idx
           ELSE MOD( away_idx + 1, num_teams + num_fake - 1 )
           END,
        week_number + 1,
        LeagueID,
        num_teams,
        num_fake
  FROM  cte
  WHERE week_number < num_teams + num_fake - 1
)
-- Finally join the cte results back to the League_Teams table to convert
-- the indexes used in calculation back to the actual team ids.
SELECT rn,
       week_number,
       NULL,
       h.id,
       a.id,
       c.leagueid
FROM   (
         -- This step isn't necessary but it keeps the results in a nice order.
         SELECT ROWNUM AS rn,
                t.*
         FROM   (
           -- Duplicate the results swapping home and away.
           SELECT week_number,
                  home_idx,
                  away_idx,
                  LeagueId
           FROM   cte
           UNION ALL
           SELECT week_number + num_teams + num_fake - 1,
                  away_idx,
                  home_idx,
                  LeagueId
           FROM   cte
         ) t
       ) c
       INNER JOIN League_Teams h
       ON ( c.home_idx = h.idx AND c.leagueId = h.leagueID )
       INNER JOIN League_Teams a
       ON ( c.away_idx = a.idx AND c.leagueId = a.leagueID )
ORDER BY rn;

SELECT * FROM fixture;

 FIXTUREID WEEKNUMBER FIXTUREDATE         HOMETEAMID AWAYTEAMID   LEAGUEID
---------- ---------- ------------------- ---------- ---------- ----------
         1          1                              1          4          1 
         2          1                              2          3          1 
         3          1                              5                     2 
         4          1                              6          9          2 
         5          1                              7          8          2 
         6          2                              2          4          1 
         7          2                              3          1          1 
         8          2                              6                     2 
         9          2                              7          5          2 
        10          2                              8          9          2 
        11          3                              3          4          1 
        12          3                              1          2          1 
        13          3                              7                     2 
        14          3                              8          6          2 
        15          3                              9          5          2 
        16          4                              8                     2 
        17          4                              9          7          2 
        18          4                              5          6          2 
        19          5                              9                     2 
        20          5                              5          8          2 
        21          5                              6          7          2 
        22          4                              4          1          1 
        23          4                              3          2          1 
        24          6                                         5          2 
        25          6                              9          6          2 
        26          6                              8          7          2 
        27          5                              4          2          1 
        28          5                              1          3          1 
        29          7                                         6          2 
        30          7                              5          7          2 
        31          7                              9          8          2 
        32          6                              4          3          1 
        33          6                              2          1          1 
        34          8                                         7          2 
        35          8                              6          8          2 
        36          8                              5          9          2 
        37          9                                         8          2 
        38          9                              7          9          2 
        39          9                              6          5          2 
        40         10                                         9          2 
        41         10                              8          5          2 
        42         10                              7          6          2