foutmelding in create function in SQL-Server 2012

[jeroenSturm]

waarom geeft hij de fout

Msg 156, Level 15, State 1, Procedure selecteer_alles, Line 6
Incorrect syntax near the keyword 'DECLARE'.

[SQL]USE twijnentest
go

CREATE function [selecteer_alles]() RETURNS TABLE
AS
RETURN (

DECLARE @totalRecords INT
DECLARE @I INT

SELECT @I = 1

SELECT @totalRecords = COUNT([Id]) FROM [dbo].[Werkzaamheden]

WHILE (@I <= @totalRecords)

BEGIN

SELECT
U.[Id]
, G.[Naam]
, W.[Omschrijving]
, U.[datum]
, CONVERT(VARCHAR,100)+'%' AS 'Status'
, W.[Norm]
, W.Id

FROM [Werkzaamheden] W
RIGHT JOIN [Uitgevoerd] U ON U.[Taak] = W.[Id] /*or left */
FULL JOIN [Gebruikers] G ON G.[Naam] = U.[Naam]

WHERE U.[Status]= 1 AND W.Id = @I

UNION

SELECT
U.[Id]
, G.[Naam]
, W.[Omschrijving]
, U.[datum]
, CONVERT(VARCHAR,0)+'%' AS 'Status'
, W.[Norm]
, W.Id
FROM [Werkzaamheden] W
LEFT JOIN [Uitgevoerd] U ON U.[Taak] = W.[Id] /*or left */
FULL JOIN [Gebruikers] G ON G.[Naam] = U.[Naam]

WHERE U.[Status]= 0 AND W.Id = @I

UNION

SELECT
U.[Id]
, G.[Naam]
, W.[Omschrijving]
, U.[datum]
, null AS 'Status'
, '' AS Norm
, W.Id
FROM [Werkzaamheden] W
RIGHT JOIN [Uitgevoerd] U ON U.[Taak] = W.[Id] /*or left */
FULL JOIN [Gebruikers] G ON G.[Naam] = U.[Naam]

WHERE U.[Status]IS NULL

SELECT @I = @I + 1

END
)[/SQL]