CREATE TABLE vehicle_details    ( vehicle_code          NUMBER
                                , vehicle_no            VARCHAR2(100)
                                , vehicle_type          VARCHAR2(100)
                                , fitness_cert_val      DATE
                                , road_tax_uptill       DATE
                                , puc                   DATE
                                , carriage_permit_exp   DATE
                                , engine_no             VARCHAR2(100)
                                , chasis_no             VARCHAR2(100)
                                , make_model            VARCHAR2(100)
                                , year_of_model         NUMBER(4)
                                , insurance_comp        VARCHAR2(200)
                                , next_prem_date        DATE
                                , CONSTRAINT vehicle_code_pk    PRIMARY KEY (vehicle_code)
                                , CONSTRAINT vehicle_no_uk      UNIQUE      (vehicle_no)
                                )

CREATE TABLE financed_vehicle_details   ( finance_code  NUMBER
                                        , finance_comp  VARCHAR2(200)
                                        , vehicle_type  VARCHAR2(100)
                                        , vehicle_code  NUMBER
                                        , vehicle_no    VARCHAR2(100)
                                        , emi_per_mon   NUMBER
                                        , due_date      VARCHAR2(30)
                                        , emi_start_dt  DATE
                                        , emi_end_dt    DATE
                                        , fin_loan_amt  NUMBER
                                        , fin_tenure    VARCHAR2(30)
                                        , rate_of_int   NUMBER(10,2)
                                        , CONSTRAINT fin_code_pk    PRIMARY KEY (finance_code)
                                        , CONSTRAINT fin_veh_fk     FOREIGN KEY (vehicle_code)  REFERENCES vehicle_details  (vehicle_code)  ON DELETE CASCADE
                                        )

DECLARE
    v_count NUMBER;
    v_name  VARCHAR2(100);
    v_date  DATE;

    CURSOR next_cur
    IS
        SELECT  vehicle_no, next_prem_date, ABS(TO_DATE(next_prem_date) - TO_DATE(SYSDATE)) c_next
        FROM    vehicle_details
        ORDER   BY 3;
BEGIN
     FOR v_next IN next_cur
     LOOP
         IF v_next.c_next <= 30
         THEN
             IF v_next.next_prem_date >= TO_DATE(SYSDATE) - 7
             THEN
                 dbms_output.put_line('Vehicle No : '||v_next.vehicle_no||' Next Prem Date : '||v_next.next_prem_date||' Days Left : '||v_next.c_next);
             END IF;
         END IF;
     END LOOP;
END;

select <column list here>
from vehicle_details
where sysdate - fitness_cert_val between 7 and 30
   or sysdate - road_tax_uptill  between 7 and 30
   or sysdate - puc              between 7 and 30
   etc.