I have created a Scalar Functions, it was created successfully, but when I call the function using select statement, it says Invalid object name \'dbo.fun_functional_score\
For some reason I was not able to use my scalar function until I referenced it using brackets, like so:
select [dbo].[fun_functional_score]('01091400003')
You have a scalar valued function as opposed to a table valued function. The from clause is used for tables. Just query the value directly in the column list.
select dbo.fun_functional_score('01091400003')
Your syntax is for table valued function which return a resultset and can be queried like a table. For scalar function do
select dbo.fun_functional_score('01091400003') as [er]
For Scalar Function Syntax is
Select dbo.Function_Name(parameter_name)
Select dbo.Department_Employee_Count('HR')