declare
    column_exists exception;
    pragma exception_init (column_exists , -01430);

begin
    execute immediate 'ALTER TABLE FISCAL_D2 ADD (PUNTOVENTA_ID NUMBER(7), CORRIDA_ID NUMBER(7), FECCORRIDA DATE)';
    exception when column_exists then null;
end;
/
declare
    column_exists exception;
    pragma exception_init (column_exists , -01430);

begin
    execute immediate 'ALTER TABLE FISCAL_D3 ADD (BOLETO_ID NUMBER(15))';
    exception when column_exists then null;
end;