How to pass parameters to Table Valued Function

Question

I want to do something like

select * from tvfHello(@param) where @param in (Select ID from Users)

Answer 1

You need to use CROSS APPLY to achieve this

select 
    f.* 
from 
    users u
    cross apply dbo.tvfHello(u.ID) f

Answer 2

That looks ok to me, except that you should always prefix your functions with their schema (usually dbo). So the query should be:

SELECT * FROM dbo.tvfHello(@param) WHERE @param IN (SELECT ID FROM Users)

Answer 3

The following works in the AdventureWorks database:

CREATE FUNCTION dbo.EmployeeByID(@employeeID int)
RETURNS TABLE
AS RETURN
(
    SELECT * FROM HumanResources.Employee WHERE EmployeeID = @employeeID
)
GO


DECLARE @employeeId int

set @employeeId=10

select * from 
EmployeeById(@employeeId) 
WHERE @EmployeeId in (SELECT EmployeeId FROM HumanResources.Employee)

EDIT

Based on Kristof expertise I have updated this sample if your trying to get multiple values you could for example do:

select * 
from HumanResources.Employee e
CROSS APPLY  EmployeeById(e.EmployeeId)
WHERE e.EmployeeId in (5,6,7,8)