问当列值为null时，不要在where条件下追加“和”子句

EN

select *
from x
where x.abc = 'ACTIVE' and
      x.start_date < sysdate and
      ( x.end_date > sysdate or x.end_date is null );

select * from x
 where x.abc = 'ACTIVE' 
   and x.start_date < sysdate 
   and NVL(x.end_date,sysdate) >= sysdate

select * from x
 where x.abc = 'ACTIVE' 
   and sysdate between x.start_date and nvl(x.end_date,sysdate);