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Use the ALTER TABLE command to modify the structure of an existing regular table by adding or deleting its columns. Tables defined with connector settings but without a schema registry can be altered.


ALTER TABLE table_name alter_option;

alter_option depends on the operation you want to perform on a table.

Adding a new column

ADD [ COLUMN ] column_name data_type [ PRIMARY KEY ]

Columns added by this command cannot be used by any existing materialized views or indexes. You must create new materialized views or indexes to reference it.

Parameter or clauseDescription
ADD [ COLUMN ]COLUMN is optional.
column_nameSpecify the name of the column you want to add.
data_typeThe data type of the new column.
-- Add a column named "age" to a table named "employees" with a data type of integer
ALTER TABLE employees ADD age int;

Dropping an existing column

DROP [ COLUMN ] [ IF EXISTS ] column_name

You cannot drop columns referenced by materialized views or indexes.

Parameter or clauseDescription
DROP [ COLUMN ]COLUMN is optional.
column_nameSpecify the column you want to remove.
IF EXISTSDo not return an error if the specified column does not exist. A notice is issued instead.
-- Remove a column named "fax" from the "employees" table
ALTER TABLE employees DROP fax;

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