MySQL syntax turn blank into NULL

I have a table called 'notes' that is varchar 125 and is occasionally populated with data.  how do I change the field from being empty to (null) where there is no data using a sql command?
pda4meAsked:
Who is Participating?
 
K VConnect With a Mentor Database ConsultantCommented:
select if(notes is '', null,notes) .... from tablename;
0
All Courses

From novice to tech pro — start learning today.