How to check if a table valued parameter is empty or not inside of a where clause?

Question

I am writing a function where I am passing a table valued parameter. In some of the cases table valued parameter can be empty.

So, my function looks like below-

CREATE FUNCTION [dbo].[testTableValueParam]
(   
    @created_date datetime = null
    ,@Ids dbo.IdList readonly
)
RETURNS TABLE 
AS
RETURN 
(
     SELECT top 10
            name
            ,scores
            ,mgr_name

        from dbo.employee
        where
            created_date = @created_date
            and 
            employeeId in (select empid from @Ids)           --ignore this condition when @Ids is empty. 
)

My table type is created as below-

CREATE TYPE [dbo].[IdList] AS TABLE(
    [empid] [nvarchar](11) NULL
)

I am calling my function from a c# code.
There are cases when the table value parameter will be empty and in those cases, when the table value parameter is empty, i want to ignore the condition in where clause.

I went through some of the links while searching my answer and the answers suggested in earlier posts didn't fix my problem.

So, right now, when @Ids parameter is empty, it gives me no record.
In some of the post they suggested not to pass a parameter for table value at all, and it will automatically treat it as an empty table.
But I have cases when I need to pass the parameter with data.
Some of the answers suggested, using if exist(select 1 from @Ids)
But, I can not use if exist in my where clause.

Please provide any suggestions.
Your responses are much appreciated.

Thanks.

Answer 1

You can use the NOT EXISTS operator something like....

CREATE FUNCTION [dbo].[testTableValueParam]
(   
    @created_date datetime = null
    ,@Ids dbo.IdList readonly
)
RETURNS TABLE 
AS
RETURN 
(
     SELECT top 10
            name
            ,scores
            ,mgr_name

        from dbo.employee
        where
           (@created_date IS NULL OR created_date = @created_date)
            and 
              ( 
                NOT EXISTS (SELECT * FROM @Ids) 
                OR
                employeeId in (select empid from @Ids)
              )            
)

Answer 2

CREATE FUNCTION [dbo].[testTableValueParam]
(   
    @created_date datetime = null
    ,@Ids dbo.IdList readonly
)
RETURNS TABLE 
AS
RETURN 
(
     SELECT top 10
            name
            ,scores
            ,mgr_name
    from dbo.employee
    where
        created_date = @created_date
        and 
        ((select count(*) from @Ids) < 1  or  employeeId in (select empid from @Ids))
        employeeId in (select empid from @Ids)           --ignore this condition when @Ids is empty. 

)