DROP EXTERNAL TABLE¶

Removes an external table from the current or specified schema. This is a metadata-only operation. None of the files that the external table refers to are dropped.

See also:

CREATE EXTERNAL TABLE , ALTER EXTERNAL TABLE , SHOW EXTERNAL TABLES , DESCRIBE EXTERNAL TABLE

Syntax¶

DROP EXTERNAL TABLE [ IF EXISTS ] <name> [ CASCADE | RESTRICT ]
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Parameters¶

name

Specifies the identifier for the external table to drop. If the identifier contains spaces, special characters, or mixed-case characters, the entire string must be enclosed in double quotes. Identifiers enclosed in double quotes are also case sensitive; for example, "My Object".

If the external table identifier is not fully qualified, in the form of db_name.schema_name.table_name or schema_name.table_name, the command looks for the external table in the current schema for the session.

CASCADE | RESTRICT

Specifies whether the external table can be dropped if foreign keys exist that reference the table:

  • CASCADE drops the external table even if it has primary or unique keys that are referenced by foreign keys in other tables.

  • RESTRICT returns a warning about existing foreign key references and doesn’t drop the external table.

Default: CASCADE

Usage notes¶

  • Unlike a standard table, dropping an external table purges it from the system. An external table can’t be recovered by using Time Travel; also, there is no UNDROP EXTERNAL TABLE command. A dropped external table must be recreated.

  • After dropping an external table, creating an external table with the same name recreates the table. No history from the old version of the external table is retained.

  • Before dropping an external table, verify that no views reference the table. Dropping an external table referenced by a view invalidates the view; that is, querying the view returns an “object does not exist” error.

  • When the IF EXISTS clause is specified and the target object doesn’t exist, the command completes successfully without returning an error.

Examples¶

Drop an external table:

SHOW EXTERNAL TABLES LIKE 't2%';

+-------------------------------+------------------+---------------+-------------+-----------------------+---------+-----------------------------------------+------------------+------------------+-------+-----------+----------------------+
| created_on                    | name             | database_name | schema_name | owner                 | comment | location                                | file_format_name | file_format_type | cloud | region    | notification_channel |
|-------------------------------+------------------+---------------+-------------+-----------------------+---------+-----------------------------------------+------------------+------------------+-------+-----------+----------------------|
| 2018-08-06 06:00:42.340 -0700 | T2               | MYDB          | PUBLIC      | MYROLE                |         | @MYDB.PUBLIC.MYSTAGE/                   |                  | JSON             | AWS   | us-east-1 | NULL                 |
+-------------------------------+------------------+---------------+-------------+-----------------------+---------+-----------------------------------------+------------------+------------------+-------+-----------+----------------------+

DROP EXTERNAL TABLE t2;

+--------------------------+
| status                   |
|--------------------------|
| T2 successfully dropped. |
+--------------------------+

SHOW EXTERNAL TABLES LIKE 't2%';

+------------+------+---------------+-------------+-------+---------+----------+------------------+------------------+-------+--------+----------------------+
| created_on | name | database_name | schema_name | owner | comment | location | file_format_name | file_format_type | cloud | region | notification_channel |
|------------+------+---------------+-------------+-------+---------+----------+------------------+------------------+-------+--------+----------------------|
+------------+------+---------------+-------------+-------+---------+----------+------------------+------------------+-------+--------+----------------------+
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Drop the table again, but don’t raise an error if the table doesn’t exist:

DROP EXTERNAL TABLE IF EXISTS t2;

+------------------------------------------------------------+
| status                                                     |
|------------------------------------------------------------|
| Drop statement executed successfully (T2 already dropped). |
+------------------------------------------------------------+
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