Question

如何为每个团队选择x最近的记录，Home and Away？

所以下面的内容让我了解斯旺西最近的主场和客场比赛，我如何为所有球队得到它？

    select d.date, d.hometeam, d.awayteam 
    from dump d
    where 
    d.hometeam = 'Swansea' 
    or d.awayteam ='Swansea'
    order by STR_TO_DATE(date, '%d/%m/%Y') desc limit 6

有关我所拥有数据的示例。我使用的是football-data.co.uk提供的CSV数据：http://www.football-data.co.uk/mmz4281/1415/E0.csv

我正在使用MySQL但是如果有一个功能或存储过程，你觉得这个目的是理想的，我可以使用SQL Server。

修改：预期输出

X      | Date    | Home Team | Away Team
----------------------------------------
Swansea| 23/03/15|Swansea    |Arsenal
----------------------------------------
Swansea| 14/03/15|Man City   |Swansea
----------------------------------------
Man Utd| 14/03/15|Man Utd    |Man City
----------------------------------------
Man Utd| 14/03/15|Man Utd    |Liverpool

虽然如果您对如何更好地展示它有任何建议，我可以接受建议。

左边是有问题的球队，如上表所示每队2个，我试图获得每队6个。

Answer 1

您只需要GROUP BY团队和日期：

SELECT d.team, d.date, d.hometeam, d.awayteam 
FROM dump d
GROUP BY team, date
ORDER BY STR_TO_DATE(date, '%d/%m/%Y');

Answer 2

您希望所有团队分别获得最近的6场比赛以下是需要注意的两件事。

在您的架构中，您没有专门的团队专栏。首先，您必须让所有团队使用HomeTeam＆amp; AwayTeam专栏。
第二件事你想为每支球队获得6场最近的比赛。团队中你意味着排名，但mysql不支持排名功能。虽然我们可以选择排名功能。

根据我的分析，这里是查询。请试一试。

SELECT
 r.homeTeamOrAwayTeam AS team
, r.date
, r.hometeam
, r.awayteam
-- , r.rank  
FROM (
SELECT
    d.date,
    d.hometeam,
    d.awayteam,
    subQuery.homeTeamOrAwayTeam,
    CASE WHEN @runningElement = subQuery.homeTeamOrAwayTeam THEN    @groupRank := (@groupRank + 1)
      ELSE  @groupRank := 1 
   END AS rank
  , CASE WHEN @runningElement = subQuery.homeTeamOrAwayTeam THEN    @runningElement := subQuery.homeTeamOrAwayTeam
      ELSE  @runningElement := subQuery.homeTeamOrAwayTeam
   END AS runnigElement
FROM
    dump d
JOIN (
  -- to get all the hometeam & awayteam in one column
    SELECT d.hometeam AS homeTeamOrAwayTeam FROM    DUMP AS d
    UNION
    SELECT d.awayteam AS homeTeamOrAwayTeam FROM    dump AS d
) AS subQuery 
     ON d.hometeam = subQuery.homeTeamOrAwayTeam OR d.awayteam = subQuery.homeTeamOrAwayTeam,
-- for ranking purpose
 (SELECT @groupRank := 1) a,
 (SELECT @runningElement := '') b
ORDER BY
    subQuery.homeTeamOrAwayTeam,
    STR_TO_DATE(d.date, '%d/%m/%Y')
) as r
-- set your criteria (e.g. if want to get only 6 results per team)
 WHERE r.rank between 1 and 6

为每个团队选择前x个记录

2 个答案: