创建视图。用空字符串替换NULL值。 SQL

Question

我想从一个表中创建一个视图，我们有一个FirstName，LastName和MiddleName列，MiddleName可以是NULL，加上薪水。我需要用MiddleName替换MiddleName和空字符串。我正在使用SQL Management Studio。 我想出了这个代码：

CREATE VIEW V_EmployeeNameJobTitle AS 
SELECT FirstName + ' ' + MiddleName + ' ' + LastName AS [Fullname], Salary FROM Employees WHERE MiddleName IS NOT NULL 
UNION SELECT FirstName + ' ' + LastName AS [Fullname], Salary FROM Employees WHERE MiddleName IS NULL 

但是，这似乎并没有工作，我想，这是不是很漂亮。任何其他建议，我可能会缩短这一点。提前致谢。

Answer 1

使用ISNULL()功能，它将取代NULL值INT您选择的值。为前：

CREATE VIEW V_EmployeeNameJobTitle AS 
SELECT FirstName + ' ' + ISNULL(MiddleName, '') + ' ' + LastName AS [Fullname], Salary 
FROM Employees 

，或者如果你不想让2位当中间名称为空，则可以进行以下操作：

CREATE VIEW V_EmployeeNameJobTitle AS 
SELECT (CASE WHEN MiddleName IS NULL THEN FirstName + ' ' + LastName 
      ELSE FirstName + ' ' + MiddleName + ' ' + LastName END) AS [Fullname], 
Salary 
FROM Employees 

Answer 2

SELECT FirstName + ' ' + 
     (case when MiddleName is null then '' else MiddleName + ' ' end) + 
     LastName AS [Fullname] 

Answer 3

使用IsNull功能

CREATE VIEW V_EmployeeNameJobTitle AS 
    SELECT FirstName + ' ' 
     + MiddleName + ' ' 
     + IsNull(LastName, '') AS [Fullname] 
    , Salary 
FROM Employees