ADD COLUMN¶

The ADD COLUMN command is used to add columns to an existing table.

Syntax¶

ALTER TABLE [schema_name.]table_name { ADD COLUMN column_def [, ...] }

schema_name ::= identifier

table_name ::= identifier

column_def ::=
  { column_name type_name [ default ] [ column_constraint ] CHECK('CS "compression_type"') }

column_name ::= identifier

column_constraint ::=
  { NOT NULL | NULL }

default ::=
  DEFAULT default_value

Parameters¶

Parameter	Description
`schema_name`	The schema name for the table. Defaults to `public` if not specified
`table_name`	The table name to apply the change to
`ADD COLUMN column_def`	A comma separated list of ADD COLUMN commands
`column_def`	A column definition. A minimal column definition includes a name identifier and a datatype. Other column constraints and default values can be added optionally

Usage Notes¶

When adding an empty column, the default values for that column will be set to NULL.

Examples¶

Adding a Simple Column with a Default Value¶

ALTER TABLE
  cool_animals
ADD
  COLUMN number_of_eyes INT DEFAULT 2 NOT NULL;

Adding Several Columns in One Command¶

ALTER TABLE
  cool_animals
ADD
  COLUMN number_of_eyes INT DEFAULT 2 NOT NULL,
ADD
  COLUMN date_seen DATE DEFAULT '2019-08-01';

Permissions¶

The role must have the DDL permission at the database or table level.