始终如 MariaDB 生成

Question

I have already used GENERATED ALWAYS AS when creating new tables. However, when I try to UPDATE TABLE an already existing table with this computed/generated column I keep on getting a 1064 error. I have also tried with the ALTER TABLE option, but haven`t had any success either.
Sample:

UPDATE TABLE crecimiento_pib
SET País GENERATED ALWAYS AS (CONCAT(CountryName,' ',CountryCode));

Thanks for the help you can provide!

Answer 1

If you are trying to add a computed column to an existing table, the syntax is:

ALTER TABLE crecimiento_pib
ADD COLUMN País varchar(200) GENERATED ALWAYS AS (CONCAT(CountryName, ' ', CountryCode));

with an appropriate size defined by the length of the CountryName and CountryCode columns (which you haven't shown).