外连接

Oracle SQL 入门

Sara Billen

Instructor

三种外连接

内连接仅返回匹配的行

左连接返回匹配行和左表的行

右连接返回匹配行和右表的行

全连接返回匹配行和两表的行

Track 与 InvoiceLine 表

SELECT t.TrackId, t.Name, i.InvoiceId, i.Quantity
  FROM Track t LEFT OUTER JOIN InvoiceLine i
  USING (TrackId)

左外连接输出

SELECT c.CustomerId, c.SupportRepId, e.FirstName, e.LastName, e.Title
FROM Customer c RIGHT OUTER JOIN Employee e
    ON c.SupportRepId = EmployeeId

右外连接输出

SELECT c.CustomerId, c.SupportRepId,e.FirstName, e.LastName, e.Title
  FROM Customer c FULL OUTER JOIN Employee e
  ON c.SupportRepId = EmployeeId

全外连接查询输出

Oracle SQL 入门