如何使用相同的Entity MYSQL选择团队名称

Question

我想获得使用相同实体的外国团队和团队主页的名称。

这是我的关系

team : id, name
Game : id, team_id, team_fk_id

我想获得team team_id名称和 team_fk_id名称。

不知道该怎么做。

这是答案：

SELECT g.id, t1.name AS home_team, t2.name AS away_team
FROM Game AS g 
JOIN team AS t1 ON t1.id = g.team_id
JOIN team AS t2 ON t2.id = g.team_fk_id
GROUP BY g.id
limit 1

Answer 1

加入,[SelfJoinSet] as ( select T1.[Contract], -- Contract from the base T1.[Date], -- Date from the base T2.[Customer], -- Customers from the current contract T2.[Action], -- ActionType of the customer -- RowNumber in order to get the last record for each customer within the current contract: [RN] = row_number() over (partition by T2.[Customer],T1.[Date] order by T2.[Date] desc) from T1 left join T1 as T2 -- SelfJoin on T1.[Contract] = T2.[Contract] -- Within the current contract and T1.[Date] >= T2.[Date] -- Get all records till the current date where T1.[Action] = '-' --Filter out all '+' actions, we'll get only '-' records anyway (for performance optimization reasons). ) select [Contract], [Date] from [SelfJoinSet] where [RN] = 1 --Show only last record per each customer group by [Contract],[Date] -- Collapse all to the base table records having count(distinct iif([Action] = '-',[Customer],NULL)) = count(distinct [Customer]) -- Leave only records where the last action is '-' for all customers 两次，一次为游戏中的每个团队加入：

team

Answer 2

您需要在团队中[['X', 'AX', 'CAX', 'XYZ'], ['X', 'AX', 'CAX', 'ABC'], ['X', 'AX', 'AXG', 'DEF'], ['X', 'AX', 'AXG', 'MNO']] 两次，例如：

JOIN