sql - 如何通过连接 PostgreSQL 中的两个表来创建 View ？

Question

我是 PostgreSQL 新手，我有两个这样的表:

1. 与会者(AttendeeId，姓名)
2. 情侣(CoupleId、AttendeeIdMan、AttendeeIdLady)

如何创建这样的 View ？

Attendees_Couple(CoupleId, Name_Man, Name_Lady)

现在，我得出了类似下面的结果，但后来我卡住了。

CREATE VIEW Attendees_Couple AS
SELECT a."Name"
FROM "Attendees" a, "Couples" c
WHERE a."AttendeeID" = c."AttendeeIdMan"....

任何提示或帮助将不胜感激!

Answer 1

你必须加入 Attendees 两次:

CREATE VIEW "Attendees_Couple" AS
SELECT c."CoupleId",
       a1."Name" AS "Name_Man",
       a2."Name" AS "Name_Lady"
FROM "Couples" AS c
   JOIN "Attendees" AS a1 ON c."AttendeeIdMan"  = a1."AttendeeId"
   JOIN "Attendees" AS a2 ON c."AttendeeIdLady" = a2."AttendeeId";

帮自己一个忙，使用小写名称!