SQL加入初学者

我对sql非常陌生，我正在努力创建一个查询。我有两张桌子：

性格

特征 名字 姓氏 性别 夫妻

对联 女性 马莱德 现在我试着这样把它组合起来：

女性名字 女性名字 男性名字 男性名字 我试过：

SELECT character.firstname AS femaleFName, character.lastname AS femaleLName
FROM Couple INNER JOIN Character ON Character.characterID = Couple.femaleID

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但是现在我正在为第二次加入而挣扎。

您所要做的就是再次加入表。要做到这一点，您必须提供别名，以免混淆表

SELECT 
cf.firstname AS femaleFName, cf.lastname AS femaleLName,
mf.firstname AS maleFName, mf.lastname AS maleLName
FROM Couple 
INNER JOIN Character AS cf ON cf.characterID = Couple.femaleID
INNER JOIN Character AS mf ON mf.characterID = Couple.maleID

关键字AS不是必需的，可以省略。

添加另一个连接，如下所示。这里c是用于区分第二个联接的表别名

SELECT character.firstname AS femaleFName, character.lastname AS femaleLName
FROM character INNER JOIN Couple ON Character.characterID = Couple.femaleID
INNER JOIN Couple c ON Character.characterID = c.maleID

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您需要使用自联接来获得所需的结果。根据需要使用以下查询获取结果

Select cf.firstname as femaleFName,
cf.lastname as femaleLName,
cm.firstname as maleFName,
cm.lastname as maleLName
from Couple c 
inner join Character cf on c.femaleID = cf.characterID
inner join Character cm on c.maleID= cm.characterID

我希望这对你有帮助

谢谢