postgresql alter table add column code example
Example 1: postgresql add column with constraint
ALTER TABLE customers
ADD COLUMN contact_name VARCHAR NOT NULL;
Example 2: alter table add column
ALTER TABLE table
ADD COLUMN column VARCHAR (255) NOT NULL AFTER column;
Example 3: alter column in table postgres
ALTER TABLE table_name
ALTER COLUMN column_name TYPE column_definition;
Example 4: postgres alter table add primary key
ALTER TABLE distributors ADD PRIMARY KEY (tablename);
Example 5: alter table add column psql
ALTER TABLE table_name
ADD column_name data_type column_constraint;
Example 6: alter table add multiple columns postgresql
ALTER TABLE customer
ADD COLUMN fax VARCHAR,
ADD COLUMN email VARCHAR;