如何有一个选择查询来生成主客桌游戏？

Question

我有一张桌子，上面有 16 个足球队的名字：

ID  Team Name
..  ..
8   MANUTD
..  
13  CHELSEA
..  ..

如何通过选择查询获得第二个表，该查询会为赛季中的每一周生成随机比赛？每支球队与其他球队比赛两次，第一次作为东道主，第二次作为客人，显然每支球队每周比赛一次。两支球队在半个赛季中从未有过两次交手，下一次他们在第二个赛季的比赛中，他们在两个领域的位置将随着主阵风顺序而改变。我怎么会有这样的选择查询？

表 2 - 上半赛季的比赛

ID  Host    Guest   Result
..  ..  ..  ..      ..
..  MANUTD  CHELSEA ..

表 2 - 第二个半赛季的比赛

..  ..  ..  ..
..  CHELSEA MANUTD  ..
..  ..  ..  ..

Answer 1

到目前为止，我开发了一个单周日历的创建。明天我将添加完整日历的循环：

DECLARE @CTR INT
DECLARE @HOST INT
DECLARE @GUEST INT
DECLARE @TEAMS TABLE (Ind INT, Name VARCHAR(50))
DECLARE @MATCHES TABLE (Ind INT, Host INT, Guest INT)

INSERT  @TEAMS (Ind, Name) VALUES ( 1, 'Arsenal')
INSERT  @TEAMS (Ind, Name) VALUES ( 2, 'Aston Villa')
INSERT  @TEAMS (Ind, Name) VALUES ( 3, 'Bournemouth')
INSERT  @TEAMS (Ind, Name) VALUES ( 4, 'Chelsea')
INSERT  @TEAMS (Ind, Name) VALUES ( 5, 'Crystal Palace')
INSERT  @TEAMS (Ind, Name) VALUES ( 6, 'Everton')
INSERT  @TEAMS (Ind, Name) VALUES ( 7, 'Leicester')
INSERT  @TEAMS (Ind, Name) VALUES ( 8, 'Liverpool')
INSERT  @TEAMS (Ind, Name) VALUES ( 9, 'Manchester City')
INSERT  @TEAMS (Ind, Name) VALUES (10, 'Manchester Utd')
INSERT  @TEAMS (Ind, Name) VALUES (11, 'Newcastle')
INSERT  @TEAMS (Ind, Name) VALUES (12, 'Norwich City')
INSERT  @TEAMS (Ind, Name) VALUES (13, 'Southampton')
INSERT  @TEAMS (Ind, Name) VALUES (14, 'Stoke City')
INSERT  @TEAMS (Ind, Name) VALUES (15, 'Sunderland')
INSERT  @TEAMS (Ind, Name) VALUES (16, 'Swansea City')
INSERT  @TEAMS (Ind, Name) VALUES (17, 'Tottenham')
INSERT  @TEAMS (Ind, Name) VALUES (18, 'Watford')
INSERT  @TEAMS (Ind, Name) VALUES (19, 'West Bromwich')
INSERT  @TEAMS (Ind, Name) VALUES (20, 'West Ham') 

SET @CTR = 0 

WHILE 1 = 1 BEGIN
   SET @CTR = @CTR + 1
   SET @HOST = 0
   SET @GUEST = 0
   WHILE 1 = 1 BEGIN
      SET @HOST  = FLOOR(RAND() * 20) + 1
      SET @GUEST = FLOOR(RAND() * 20) + 1
      IF NOT EXISTS(SELECT Host  From @MATCHES WHERE Host  = @HOST ) AND
         NOT EXISTS(SELECT Host  From @MATCHES WHERE Host  = @GUEST) AND
         NOT EXISTS(SELECT Guest From @MATCHES WHERE Guest = @HOST ) AND
         NOT EXISTS(SELECT Guest From @MATCHES WHERE Guest = @GUEST) AND
         @HOST <> @GUEST BREAK
   END
   INSERT @MATCHES (Ind, Host, Guest) VALUES ( 1, @HOST, @GUEST)
   IF @CTR = 10 BREAK
END

SELECT A.Ind, B.Name, C.Name FROM @MATCHES A
JOIN @TEAMS B ON Host = B.Ind
JOIN @TEAMS C ON Guest = C.Ind

Answer 2

因为这使用了一些循环和表变量，所以对于大型集合来说，它不是最有效的解决方案。但是，如果您只对 16 个团队执行一次此操作，则可以：

create table Teams (team varchar(5))
insert into Teams(team) values
('a'),
('b'),
('c'),
('d'),
('e'),
('f'),
('g'),
('h'),
('i'),
('j'),
('k'),
('l'),
('m'),
('n'),
('o'),
('p')

使用独占交叉连接来创建独特的对决：

declare @Matchups table (home varchar(5), away varchar(5), orderNo float)
insert into @Matchups
select * from (
select x1.team as home, x2.team as away,RAND(CHECKSUM(NEWID())) as orderNo from @x x1
cross join @x x2
where x1.tm <> x2.tm
) a

declare @half1 table (home varchar(5), away varchar(5), week int)
declare @matchup int = 15
declare @week int = 15

创建第一场比赛，然后在表格中循环，确保没有球队在同一周比赛两次并且没有重复比赛

delete top(1) from @Matchups
output deleted.home,deleted.away,@week into @half1

set @matchup = @matchup - 1

while @week > 0
begin
    while @matchup > 0
    begin
        delete top(1) s
        output deleted.home,deleted.away,@week into @half1
        from @Matchups s
        where not exists (
                    select 1 from @half1 m
                    where ((m.away = s.away
                    or m.away = s.home 
                    or m.home = s.away
                    or m.home = s.home)
                    and week = @week)
                    or
                    (m.away = s.away
                    and m.home = s.home)
                    or
                    (m.away = s.home
                    and m.home = s.away)
                    )
        set @matchup = @matchup - 1
    end
    set @week = @week - 1
    set @matchup = 15
end

set @week = 15
set @matchup = 8

对于下半场，只需以相反的主客场顺序将值插入表中，然后随机化比赛。

declare @half2 table (home varchar(5), away varchar(5), week int)
while @week > 0
begin
    while @matchup > 0
    begin 
        insert into @half2
        select top 1 away,home,@week from 
        (select *,RAND(CHECKSUM(NEWID())) as orderNo from @half1 h1
        where not exists (
                        select 1 from @half2 h2
                        where (h1.away = h2.away 
                        or h1.away = h2.home 
                        or h1.home = h2.away 
                        or h1.home = h2.home)
                        and week = @week)) a
        order by orderNo
        set @matchup = @matchup - 1
    end
    set @matchup = 8
    set @week = @week - 1
end


select *,1 as Half from @half1
union all
select *,2 as Half from @half2