How to set to NULL a datetime with 0000-00-00 00:00:00 value?

Question

I need to change a few values on my DB.

I forgot to set nullable to the table and it set to 0000-00-00 00:00:00 by default.

Now I need to convert that value in <

Answer 1

What worked for me is:

1. Set the field from datetime to varchar(191).
2. Update all rows with field = '0000-00-00 00:00:00' to NULL.
3. Set the field back to datetime.