SELECT
  serviceSupplierLinkID
INTO
  :serviceSupplierLinkID 
FROM
  ServiceSupplierLink 
WHERE supplierConcernRoleID = :supplierConcernRoleID 
  AND serviceSupplierLinkID <> :serviceSupplierLinkID 
  AND statusCode = :statusCode 
  AND serviceID = :serviceID 
  AND 
  (
    
    (
      endDate >= :startDate 
      OR endDate IS NULL 
    ) 
    AND 
    (
      startDate <= :endDate 
      OR :endDate IS NULL 
    ) 
  )