错误：将varchar值'...'转换为数据类型int时转换失败

Question

declare   @EmployeeID INT
declare   @age       varchar(4)
   select      @age = 'birthdate'  
   select      @EmployeeID = 'BusinessEntityID'

select BusinessEntityID , Birthdate 
from AdventureWorks2016.HumanResources.Employee
where BirthDate=@age  and  BusinessEntityID= @EmployeeID

错误是：

  

消息245，级别16，状态1，第58行转换时转换失败   数据类型为int的varchar值“ BusinessEntityID”。

Answer 1

只需输入ID，而不是字符串'BusinessEntityID'：

 select      @EmployeeID = 10