mysql - Why there is Invalid Default Value for the table in mysql

Question

I executed the query below

ALTER TABLE `users` CHANGE `phone` `phone` VARCHAR( 20 ) 
    CHARACTER SET latin1 COLLATE latin1_swedish_ci NOT NULL DEFAULT NULL 

and result was ...

#1067 - Invalid default value for 'phone' 

Answer 1

You're not allowing it to be null and then setting it to null as a default value.

Answer 2

You've set a default value of NULL for a column that can't be NULL