>>>

SET ANSI_NULLS ON
>>>GO
>>>SET QUOTED_IDENTIFIER ON
>>>GO
>>>-- =============================================
>>>-- Author:		<Author,,Name>
>>>-- Create date: <Create Date, ,>
>>>-- Description:	<Description, ,>
>>>-- =============================================
>>>CREATE FUNCTION GetDatePaidTo
>>>(
>>>	-- Add the parameters for the function here
>>>	@PolicyHeaderPK uniqueidentifier
>>>)
>>>RETURNS datetime
>>>AS
>>>BEGIN
>>>	-- Declare the return variable here
>>>	DECLARE @DatePaidTo datetime
>>>
>>>	-- Add the T-SQL statements to compute the return value here
>>>	declare @MonthsToAdd int
>>>	declare @PremiumMode varchar(15)
>>>	declare @IssueDate datetime
>>>	
>>>	SELECT @MonthsToAdd = SUM(
>>>		CASE [PremiumMode]  -- Add table alias here
>>>			 WHEN 'Monthly' THEN NumberOfPremiums * 1 -- add table alias for NumberOfPremiums
>>>			 WHEN 'Quarterly' THEN NumberOfPremiums * 3
>>>			 WHEN 'Semi-Annually' THEN NumberOfPremiums * 6
>>>			 WHEN 'Annually' THEN NumberOfPremiums * 12
>>>			 ELSE 0
>>>		END )
>>>	FROM [dbo].[ReceiptDetails]
>>>	inner join [dbo].[Receipts] on ReceiptFK = ReceiptPK  -- looks like this join is not needed, also, add aliases to tables
>>>	WHERE 
>>>		([PolicyHeaderFK] = @PolicyHeaderPK
>>>		AND ReceiptTypeFK = 3)
>>>
>>>	SELECT @IssueDate = IssueDate -- add alias here
>>>	FROM [dbo].[Policyheaders]
>>>		INNER JOIN [dbo].[Policies]	ON [PolicyHeaderPK] = [PolicyHeaderFK]
>>>		INNER JOIN (SELECT [PolicyHeaderFK], MAX(LastChanged) as LastChanged
>>>						FROM [dbo].[Policies]
>>>						GROUP BY [PolicyHeaderFK]) subquery ON [Policies].[PolicyHeaderFk] = subquery.policyHeaderFK AND Policies.LastChanged = subquery.LastChanged
>>>		inner join [dbo].[Plans] on [PlanFK] = [PlanPK] -- do we need all these joins?
>>>		inner join [dbo].[Clients] on [ClientFK] = [ClientPK]
>>>		INNER JOIN [dbo].[Status] on [StatusFK] = [StatusPK]
>>>	WHERE 
>>>		([PolicyHeaderPK] = @PolicyHeaderPK)
>>>
>>>	SET @DatePaidTo = DATEADD(M, @MonthsToAdd, @IssueDate)
>>>	
>>>	-- Return the result of the function
>>>	RETURN @DatePaidTo
>>>
>>>END
>>>GO

>>>
>>>Thanks
>>
>>I put some comments. It may be OK. Keep in mind that scalar functions in T-SQL may be slow.
>>Also, I suggest to add table alias for each field, as if someone needs to maintain this code, it's not clear which table which field belongs to.
>
>Hi again Naomi,
>
>how do I use this function in a computed field now? I've added the field to the table and put GetDatePaidTo(PolicyHeaderPK) as the formula but it tells me "Error validating the formula for the column" when I try to save the table definition.


Looks like I need to enter it like this:

([dbo].[GetDatePaidTo]([PolicyHeaderPK]))