ERROR 1067 (42000): Invalid default value for 'created_at'

Question

The problem is because of sql_modes. Please check your current sql_modes by command:

show variables like 'sql_mode' ; 

And remove the sql_mode "NO_ZERO_IN_DATE,NO_ZERO_DATE" to make it work. This is the default sql_mode in mysql new versions.

You can set sql_mode globally as root by command:

set global sql_mode = 'ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';

Simply, before you run any statements put this in the first line:

SET sql_mode = '';

PLEASE NOTE: this statement should be used only in development, not in production.

Try and run the following command:

ALTER TABLE `investments` 
MODIFY created_at TIMESTAMP 
DEFAULT CURRENT_TIMESTAMP 
NOT NULL;

and

ALTER TABLE `investments` 
MODIFY updated_at TIMESTAMP 
DEFAULT CURRENT_TIMESTAMP 
NOT NULL;

The reason you are getting this error is because you are not setting a default value for the created_at and updated_at fields. MySQL is not accepting your command since the values for these columns cannot be null.

I came across the same error while trying to install a third party database. I tried the solution proposed unsuccessfully i.e.
SET sql_mode = '';

Then I tried the command below which worked allowing the database to be installed
SET GLOBAL sql_mode = '';

In my case, I have a file to import.
So I simply added SET sql_mode = ''; at the beginning of the file and it works!