问题描述
我遇到了SQL连接问题.
I am having trouble with a SQL join question.
我有一个表EMPLOYEE和EmpID, FirstName, LastName, Email, Phone
我还有另一个具有两个字段"Name" & "OtherName"的表OTHERNAME.
I have another table OTHERNAME with 2 fields "Name" & "OtherName".
此表包含诸如"James", "Jim"; "Thomas", "Tom"; "Steven", "Steve"的查找值.
This table contains lookup values such as "James", "Jim"; "Thomas", "Tom"; "Steven", "Steve".
我想编写一个查询，该查询将返回行
I want to write a query which will return rows
EmpID, FirstName, LastName, Email, Phone, OtherName
where Employee.Firstname = OTHERName.Name
推荐答案
Select e.EmpID, e.FirstName, e.LastName, e.Email, e.Phone, o.OtherName
From Employee e
Left Outer Join OtherName o on e.FirstName = o.Name
从您的评论看来，您实际上想要一个外部联接.
From your comments it sounds like you actually want an outer join.
(来自注释)外部联接将返回所有雇员，如果有一个雇员，还将返回另一个雇员姓名，否则其他雇员姓名将为空值，您可以在代码中处理该空值.内部联接将结果限制为仅具有匹配记录的员工.
(From Comments) An outer join would return all employees, along with an Othername if there is one, otherwise Othername would be a null value which you could handle in code. An inner join limits the results to only employees with a matching record.
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