Jaa

RESTORE

  • Artikkeli

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime

Restores a Delta table to an earlier state. Restoring to an earlier version number or a timestamp is supported.

This page contains details for using the correct syntax with the RESTORE command. See Work with Delta Lake table history for more guidance on navigating Delta Lake table versions with this command.

Syntax

RESTORE [ TABLE ] table_name [ TO ] time_travel_version

time_travel_version
 { TIMESTAMP AS OF timestamp_expression |
   VERSION AS OF version }

Parameters

  • table_name

    Identifies the Delta table to be restored. The table name must not use a temporal specification or options specification.

  • timestamp_expression can be any one of:

    • '2018-10-18T22:15:12.013Z', that is, a string that can be cast to a timestamp
    • cast('2018-10-18 13:36:32 CEST' as timestamp)
    • '2018-10-18', that is, a date string
    • current_timestamp() - interval 12 hours
    • date_sub(current_date(), 1)
    • Any other expression that is or can be cast to a timestamp

  • version is a long value that can be obtained from the output of DESCRIBE HISTORY table_spec.

Neither timestamp_expression nor version can be subqueries.

Examples

-- Restore the employee table to a specific timestamp
> RESTORE TABLE employee TO TIMESTAMP AS OF '2022-08-02 00:00:00';
 table_size_after_restore num_of_files_after_restore num_removed_files num_restored_files removed_files_size restored_files_size
                      100                          3                 1                  0                574                   0

-- Restore the employee table to a specific version number retrieved from DESCRIBE HISTORY employee
> RESTORE TABLE employee TO VERSION AS OF 1;
 table_size_after_restore num_of_files_after_restore num_removed_files num_restored_files removed_files_size restored_files_size
                      100                          3                 1                  0                574                   0

-- Restore the employee table to the state it was in an hour ago
> RESTORE TABLE employee TO TIMESTAMP AS OF current_timestamp() - INTERVAL '1' HOUR;
 table_size_after_restore num_of_files_after_restore num_removed_files num_restored_files removed_files_size restored_files_size
                      100                          3                 1                  0                574                   0