Multiple values in a single parameter of a scalar function - sql

Question

Is there a way to input multiple values in a single parameter of a scalar-valued function in SQL Server 2008 R2 and have it filter data by that parameter using both values?
For example I would like to do the following
SET #Salesperson='BILL' OR 'MOSES'
SELECT Sum(SalesDollars)
FROM Invoices
WHERE Invoices.Salesperson = #Salesperson
I attempted to use the following as the WHERE clause, but this didnt work either.
SET #Salesperson='BILL','MOSES'
SELECT Sum(SalesDollars)
FROM Invoices
WHERE Invoices.Salesperson IN (#Salesperson)
Would it be easier if i were dealing with integers as opposed to varchar values?
Any help would be absolutely appreciated!

Answer 1

You need to use table-valued parameters. Look it up on technet or msdn
Best part of it that your table-valued parameters can have multiple columns.
Note however that you have to define TVP parameter as readonly. So if you want to return similar set from your function you will need to create another variable inside your function.
Example:
CREATE TYPE Names AS TABLE
( Name VARCHAR(50));
GO
/* Create a procedure to receive data for the table-valued parameter. */
CREATE PROCEDURE dbo.mySP
#n Names READONLY
AS
SELECT Sum(SalesDollars)
FROM
WHERE Invoices.Salesperson in (select Name from #n)
GO
CREATE FUNCTION dbo.myFun(#n Names READONLY) returns int
AS
SELECT Sum(SalesDollars)
FROM
WHERE Invoices.Salesperson in (select Name from #n)
GO
/* Declare a variable that references the type. */
DECLARE #names AS Names;
/* Add data to the table variable. */
INSERT INTO #names (Name)
VALUES ('BILL'),('MOSES')
-- using stored procedure with TVP
EXEC dbo.mySP #names
-- using function with TVP
select dbo.myFun(#names)
GO

Answer 2

This could be done this way:
SET #Salesperson='BILL,MOSES'
SELECT *
FROM YourTable
WHERE Invoices.Salesperson IN (SELECT * FROM dbo.split(#Salesperson,','))
This is how you split the values.

Answer 3

I would typically do this using a user defined table type: SQL Fiddle Example.
CREATE TYPE <schema>.SalespersonList AS TABLE
(
Name varchar(32)
)
You may have to grant execute permissions on the type:
GRANT EXECUTE ON TYPE::<schema>.SalespersonList TO <user>
Then you can create a function to use it:
CREATE FUNCTION <schema>.fnGetTotalSales
(
#nameList <schema>.SalespersonList READONLY
)
RETURNS INT
AS
BEGIN
DECLARE #ret INT
SELECT #ret = Sum(SalesDollars)
FROM Invoices i
INNER JOIN #nameList nl ON nl.Name = i.Salesperson
RETURN #ret
END
Then you would just insert your list into the type and call the function:
DECLARE #salesPersonList <schema>.SalespersonList
INSERT INTO #salesPersonList (Name)
SELECT 'Bill'
UNION
SELECT 'Moses'
SELECT <schema>.fnGetTotalSales(#salesPersonList)