創建視圖。用空字符串替換NULL值。 SQL

Question

我想從一個表中創建一個視圖，我們有一個FirstName，LastName和MiddleName列，MiddleName可以是NULL，加上薪水。我需要用MiddleName替換MiddleName和空字符串。我正在使用SQL Management Studio。 我想出了這個代碼：

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，這似乎並沒有工作，我想，這是不是很漂亮。任何其他建議，我可能會縮短這一點。提前致謝。

Answer 1

使用ISNULL()功能，它將取代NULL值INT您選擇的值。爲前：

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

，或者如果你不想讓2位當中間名稱爲空，則可以進行以下操作：

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