替换联接中的 NULL 值

Question

替换 Null 值有些困难。

数据库试用的屏幕截图

数据集：

Computer -  (Compid, Make, Model, Myear)
Employee - (Id, Ename, Doj, Salary, Bonus, Dept, Designation, Manager, Compid)

我的代码：

SELECT E.Ename , E.Dept, C.MODEL FROM Employee E 
       LEFT OUTER JOIN Computer C ON E.Compid = C.Compid

结果未显示任何空值

Answer 1

您可以使用coalesce()

SELECT E.Ename , E.Dept, coalesce(C.MODEL,'Not allocated') as model 
FROM Employee E LEFT OUTER JOIN Computer C ON E.Compid = C.Compid

Replace NULL values in Joins