Mysql Self Join在同一个表中查找父子关系

Question

我试图计算一段时间内男性赛马(Sire)的所有后代赢得的金额.由Sire列出的最赚钱金额.我运行查询并得到结果我有一个问题,我不能显示公牛名称,只有他们的ID.

SELECT  `horses`.`SireID` AS  `SireID` , `horses`.`HorseName` AS  `Sire Name`, 
                  COUNT(  `runs`.`HorsesID` ) AS  `Runs` , 
                  COUNT( 
                           CASE WHEN  `runs`.`Finish` =1
                                THEN 1 
                                ELSE NULL 
                                END ) AS  `Wins` , 
                  CONCAT( FORMAT( (
                                COUNT( 
                                       CASE WHEN  `runs`.`Finish` =1
                                            THEN 1 
                                            ELSE NULL 
                                            END ) / COUNT
                                    (  `runs`.`TrainersID` ) ) *100, 0 ) ,  '%'
                  ) AS  `Percent` , 
           FORMAT( SUM(  `runs`.`StakeWon` ) , 0 ) AS  `Stakes` 
FROM runs
INNER JOIN horses ON runs.HorsesID = horses.HorsesID
INNER JOIN races ON runs.RacesID = races.RacesID
WHERE  `races`.`RaceDate` >= STR_TO_DATE(  '2012,07,01',  '%Y,%m,%d' ) 
AND  `races`.`RaceDate` < STR_TO_DATE(  '2012,07,01',  '%Y,%m,%d' ) + INTERVAL 1 
MONTH 
AND `horses`.`SireID`  <> `horses`.`HorsesID`
GROUP BY  `horses`.`SireID`, `horses`.`HorseName`
ORDER BY SUM(  `runs`.`StakeWon` ) DESC

以马桌上的记录为例,马有马匹,他们也有一个sireID(他们的父亲).sireID在同一个表中的另一个记录中具有等效的horsesID,因为它也是一匹马

基本上我需要将horseName映射到sireID.

我认为自我加入会起作用.

 `AND `horses`.`SireID`  <> `horses`.`HorsesID`` 

但它不会返回与SireID相对应的正确Sire名称.

Answer 1

你可以在桌子上做一个JOIN.这是一个更简单的例子:

SELECT Horses.HorseID, Horses.HorseName, Horses.SireID, b.HorseName as SireName
FROM Horses
LEFT JOIN Horses b ON (Horses.SireID = b.HorseID)

您可以从这里找出如何添加条件.