How to compare mySQL dates

[Alberto]

There is a table in which, among other things, two fields

activeFrom [date] DEFAULT NULL
activeTill [date] DEFAULT NULL

Data are entered in the table from different sources, so the fields have different meanings: NULL♪ 0000-00-00 and some date (e.g.) 2015-12-16♪

Objective:
SQL request to remove all lines where the current date falls between activeFrom and activeTill♪
In the field. NULL or 0000-00-00counting true. (i.e., now 2015-12-16, in the table activeFrom = NULL and activeTill = '2016-01-01'I need a record.
activeTill - Date inclusive

---

In principle, I did a comparison of all options.

SELECT * FROM [table] 
WHERE (
    (activeFrom='0000-0-0' AND activeTill='0000-0-0') OR
    (activeFrom<>'0000-0-0' AND activeTill<>'0000-0-0' AND NOW() BETWEEN activeFrom AND CONCAT(activeTill, ' 23:59:59')) OR
    (activeFrom='0000-0-0' AND activeTill<>'0000-0-0' AND NOW()<CONCAT(activeTill, ' 23:59:59') OR
    (activeFrom<>'0000-0-0' AND activeTill='0000-0-0' AND activeFrom<NOW()))
)

But I have a suspicion that we can solve something more compelling. Without this terrible transfer.

Can someone offer options?

[kalena]

select *
  from table
 where curdate() between (if(ifnull(activeFrom,'0000-00-0')='0000-00-0',curdate(),activeFrom))
                     and (if(ifnull(activeTill,'0000-00-0')='0000-00-0',now(),activeTill))