UPDATE dbo.PL_REQUEST_PROCESS SET PARENT_PROCESS_ID=(SELECT TOP 1 PROCESS_ID FROM dbo.PL_REQUEST_PROCESS T WHERE  T.PROCESS_ID <>'APPROVE' AND T.REQ_ID=dbo.PL_REQUEST_PROCESS.REQ_ID
ORDER BY REQ_ID,ID DESC) WHERE PL_REQUEST_PROCESS.PROCESS_ID='APPROVE' AND PL_REQUEST_PROCESS.PARENT_PROCESS_ID IS NULL