mysql 时间年

Question

我在锦标赛数据库中建模和实施 "temporal" 事件时遇到问题。

我有三个实体：球员、球队、转会、冠军，我想跟踪球员在冠军期间的转会（球员可以在冠军期间转会到另一支球队）

championship(id_championship*, name, year*)
player (id_player*, name, number, id_team*)
team (id_team, name)
transfer (id_player*, id_team_from*, id_team_to*, transfer _date)

谢谢。

Answer 1

您可以试试这个查询，例如：

Select T1.id_player, T1.id_team_from as Team, T1.Transfer_date as PeriodFrom, 
T2.Transfer_date as PeriodTo
            from  
        (Select id_player,id_team_from, id_team_to, Transfer_date, 
        row_number() over (partition by id_player order by transfer_date desc) RN1)T1
            inner join 
        (Select id_player,id_team_from, id_team_to, Transfer_date, 
        row_number() over (partition by id_player order by transfer_date desc) RN2)T2
            on T1.RN1=T2.RN2+1
            and T1.id_player=T2.id_player

它应该 return 所有球员和他们参加过的球队，从 PeriodFrom 到 PeriodTo。

mysql 时间年

mysql temporal year

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