How to alter table to add new date time column that insert date time on each row creation?

Question

I created a table now I want to add date time column but I want to current date time of each row insertion.

I have written syntax like this: ALTER TABLE particle_photon ADD COLUMN dt_created NOT NULL default CURRENT_TIMESTAMP AFTER humidity;

but I get error:

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'NOT NULL default CURRENT_TIMESTAMP  AFTER  humidity' at line 1

Answer 1

You are missing the declaration of the datatype (I assume TIMESTAMP ):

ALTER TABLE particle_photon 
ADD COLUMN dt_created TIMESTAMP
NOT NULL DEFAULT CURRENT_TIMESTAMP  AFTER humidity;

Demo on DB Fiddle :

CREATE TABLE particle_photon(id INT PRIMARY KEY, humidity INT, lastcol INT);

ALTER TABLE particle_photon 
ADD COLUMN dt_created TIMESTAMP
NOT NULL DEFAULT CURRENT_TIMESTAMP  AFTER humidity;