and or operator not working properly in mysql

this is my select query i want to fetch records who have status like "P" or "I" but it not shows me records

what is wrong if me give or condition in status

     SELECT designmaster.designMasterId,desWet,item.itemnm,designMaster.dNo,DATE_FORMAT(designDate,'%d-%m-%Y') AS designDate
                                 FROM process
                             LEFT JOIN designMaster ON designMaster.designMasterId = process.designMasterId
                              LEFT JOIN item ON item.itemId = designMaster.itemId
                              WHERE nextProcessId = ".$nextProcessId."
                                AND status = 'I'
                                OR  status = 'P'
                            GROUP BY designmaster.designMasterId