How can a not null constraint be dropped?

Let's say there's a table created as follows:

create table testTable ( colA int not null )

How would you drop the not null constraint? I'm looking for something along the lines of

ALTER TABLE testTable ALTER COLUMN colA DROP NOT NULL;

which is what it would look like if I used PostgreSQL. To my amazement, as far as I've been able to find, the MySQL docs, Google and yes, even Stackoverflow (in spite of dozens or hundreds of NULL-related questions) don't seem to lead towards a single simple SQL statement which will do the job.

Solution 1:

I would try something like this

ALTER TABLE testTable MODIFY COLUMN colA int;

Solution 2:

In MySQL, nullability is a part of the datatype, not a constraint. So:

ALTER TABLE testTable MODIFY COLUMN colA int null; 

Solution 3:

The syntax was close its actually:

ALTER TABLE testTable CHANGE colA colA int null;

Solution 4:

Try

ALTER TABLE testTable MODIFY COLUMN columnA int;