Question

我想从一个表中创建一个视图，其中我们有一个FirstName，LastName和MiddleName列，其中MiddleName可能是NULL，加上一个工资。我需要将MiddleName替换为空字符串，而不是MiddleName。我正在使用SQL Management Studio。我想出了这段代码：

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

但这似乎并不像我想的那样有效，并且它不是很漂亮。任何其他建议我如何缩短这个。提前谢谢。

Answer 1

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

Answer 2

使用ISNULL()函数，它将NULL值替换为您选择的值。例如：

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

如果您不希望在中间名为空时获得2个空格，则可以执行以下操作：

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 3

使用IsNull功能

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

创建视图。用空字符串替换NULL值。 SQL

3 个答案: