ADD COLUMN
The ADD COLUMN
command is used to add columns to an existing table.
Syntax
The following is the correct syntax for adding a column to an existing table:
alter_table_add_column_statement ::=
ALTER TABLE [schema_name.]table_name { ADD COLUMN column_def [, ...] }
;
table_name ::= identifier
schema_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
The following parameters can be used for adding a table:
Parameter |
Description |
---|---|
|
The schema name for the table. Defaults to |
|
The table name to apply the change to. |
|
A comma separated list of ADD COLUMN commands |
|
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
This example shows how to add 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
This example shows how to add 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';
Adding Compressed Column
ALTER TABLE coo_animals ADD COLUMN animal_salary INT CHECK('CS "dict"');
Follow SQreamDB compression guide for compression types and methods.
Permissions
The role must have the DDL
permission at the database or table level.