# DROP COLUMN

The `DROP COLUMN` statement is part of `ALTER TABLE` and removes columns from a table.

## Synopsis

## Required privileges

The user must have the `CREATE` privilege on the table.

## Parameters

Parameter | Description
--- | ---
`table_name` | The name of the table with the column you want to drop.
`name` | The name of the column you want to drop. When a column with a `CHECK` constraint is dropped, the `CHECK` constraint is also dropped.
`CASCADE` | Drop the column even if objects (such as views) depend on it; drop the dependent objects, as well. `CASCADE` does not list objects it drops, so should be used cautiously. However, `CASCADE` will not drop dependent indexes; you must use `DROP INDEX`. `CASCADE` will drop a column with a foreign key constraint if it is the only column in the reference.
`RESTRICT` | (Default) Do not drop the column if any objects (such as views) depend on it.

## Viewing schema changes

Whenever you initiate a schema change, CockroachDB registers it as a job, which you can view with `SHOW JOBS`.

## Examples

### Drop columns

If you no longer want a column in a table, you can drop it.

    > ALTER TABLE orders DROP COLUMN billing_zip;

### Prevent dropping columns with dependent objects (`RESTRICT`)

If the column has dependent objects, such as views, CockroachDB will not drop the column by default; however, if you want to be sure of the behavior you can include the `RESTRICT` clause.

    > ALTER TABLE orders DROP COLUMN customer RESTRICT;

    pq: cannot drop column "customer" because view "customer_view" depends on it

### Drop column and dependent objects (`CASCADE`)

If you want to drop the column and all of its dependent options, include the `CASCADE` clause.

Warning:
`CASCADE` does not list objects it drops, so should be used cautiously.

    > SHOW CREATE customer_view;

    +---------------+----------------------------------------------------------------+
    | table_name    | create_statement                                               |
    +---------------+----------------------------------------------------------------+
    | customer_view | CREATE VIEW customer_view AS SELECT customer FROM store.orders |
    +---------------+----------------------------------------------------------------+

    > ALTER TABLE orders DROP COLUMN customer CASCADE;

    > SHOW CREATE customer_view;

    pq: view "customer_view" does not exist

## See also

- `DROP CONSTRAINT`
- `DROP INDEX`
- `ALTER TABLE`