Migration of create statement from SQL Server to MySQL
This answer will apply to your question : Insert Value based on One Column based on Value on another Column 

AFAIK, and based on the link posted, you cannot create a computed column in MySQL.  You should either: 


Do the calculation outside of the database, when inserting OR
Create a trigger on the table to populate the value for you OR
Create a view to represent the data in the way you want.