Answers for "postgres sql alter table add column"

postgresql add column with constraint

ALTER TABLE customers 
ADD COLUMN contact_name VARCHAR NOT NULL;

alter table add column psql

ALTER TABLE table_name
ADD column_name data_type column_constraint;

alter table add multiple columns postgresql

ALTER TABLE customer 
ADD COLUMN fax VARCHAR,
ADD COLUMN email VARCHAR;

postgres how to add field created at

CREATE TABLE my_table
(
	id serial NOT NULL,
    user_name text,
	created_at timestamp with time zone DEFAULT CURRENT_TIMESTAMP //here
)