SHOW INDEX

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The SHOW INDEX statement returns index information for a table or database.

Required privileges

The user must have any privilege on the target table or database.

Aliases

In CockroachDB, the following are aliases for SHOW INDEX:

  • SHOW INDEXES
  • SHOW KEYS

Synopsis

SHOW INDEX INDEXES KEYS FROM table_name DATABASE database_name WITH COMMENT

Parameters

Parameter Description
table_name The name of the table for which you want to show indexes.
database_name The name of the database for which you want to show indexes.

Response

The following fields are returned for each column in each index.

Field Description
table_name The name of the table.
index_name The name of the index.
non_unique Whether or not values in the indexed column are unique. Possible values: true or false.
seq_in_index The position of the column in the index, starting with 1.
column_name The indexed column.
direction How the column is sorted in the index. Possible values: ASC or DESC for indexed columns; N/A for stored columns.
storing Whether or not the STORING clause was used to index the column during index creation. Possible values: true or false.
implicit Whether or not the column is part of the index despite not being explicitly included during index creation. Possible values: true or false

At this time, primary key columns are the only columns that get implicitly included in secondary indexes. The inclusion of primary key columns improves performance when retrieving columns not in the index.

Example

Setup

The following examples use MovR, a fictional vehicle-sharing application, to demonstrate CockroachDB SQL statements. For more information about the MovR example application and dataset, see MovR: A Global Vehicle-sharing App.

To follow along, run cockroach demo to start a temporary, in-memory cluster with the movr dataset preloaded:

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$ cockroach demo

Show indexes for a table

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> CREATE INDEX ON users (name);
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> SHOW INDEX FROM users;
  table_name |   index_name   | non_unique | seq_in_index | column_name | direction | storing | implicit
+------------+----------------+------------+--------------+-------------+-----------+---------+----------+
  users      | primary        |   false    |            1 | city        | ASC       |  false  |  false
  users      | primary        |   false    |            2 | id          | ASC       |  false  |  false
  users      | users_name_idx |    true    |            1 | name        | ASC       |  false  |  false
  users      | users_name_idx |    true    |            2 | city        | ASC       |  false  |   true
  users      | users_name_idx |    true    |            3 | id          | ASC       |  false  |   true
(5 rows)

Show indexes for a database

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> SHOW INDEXES FROM DATABASE movr;
          table_name         |                  index_name                   | non_unique | seq_in_index | column_name  | direction | storing | implicit
+----------------------------+-----------------------------------------------+------------+--------------+--------------+-----------+---------+----------+
  users                      | primary                                       |   false    |            1 | city         | ASC       |  false  |  false
  users                      | primary                                       |   false    |            2 | id           | ASC       |  false  |  false
  vehicles                   | primary                                       |   false    |            1 | city         | ASC       |  false  |  false
  vehicles                   | primary                                       |   false    |            2 | id           | ASC       |  false  |  false
  vehicles                   | vehicles_auto_index_fk_city_ref_users         |    true    |            1 | city         | ASC       |  false  |  false
  vehicles                   | vehicles_auto_index_fk_city_ref_users         |    true    |            2 | owner_id     | ASC       |  false  |  false
  vehicles                   | vehicles_auto_index_fk_city_ref_users         |    true    |            3 | id           | ASC       |  false  |   true
  rides                      | primary                                       |   false    |            1 | city         | ASC       |  false  |  false
  rides                      | primary                                       |   false    |            2 | id           | ASC       |  false  |  false
  rides                      | rides_auto_index_fk_city_ref_users            |    true    |            1 | city         | ASC       |  false  |  false
  rides                      | rides_auto_index_fk_city_ref_users            |    true    |            2 | rider_id     | ASC       |  false  |  false
  rides                      | rides_auto_index_fk_city_ref_users            |    true    |            3 | id           | ASC       |  false  |   true
  rides                      | rides_auto_index_fk_vehicle_city_ref_vehicles |    true    |            1 | vehicle_city | ASC       |  false  |  false
  rides                      | rides_auto_index_fk_vehicle_city_ref_vehicles |    true    |            2 | vehicle_id   | ASC       |  false  |  false
  rides                      | rides_auto_index_fk_vehicle_city_ref_vehicles |    true    |            3 | city         | ASC       |  false  |   true
  rides                      | rides_auto_index_fk_vehicle_city_ref_vehicles |    true    |            4 | id           | ASC       |  false  |   true
  vehicle_location_histories | primary                                       |   false    |            1 | city         | ASC       |  false  |  false
  vehicle_location_histories | primary                                       |   false    |            2 | ride_id      | ASC       |  false  |  false
  vehicle_location_histories | primary                                       |   false    |            3 | timestamp    | ASC       |  false  |  false
  promo_codes                | primary                                       |   false    |            1 | code         | ASC       |  false  |  false
  user_promo_codes           | primary                                       |   false    |            1 | city         | ASC       |  false  |  false
  user_promo_codes           | primary                                       |   false    |            2 | user_id      | ASC       |  false  |  false
  user_promo_codes           | primary                                       |   false    |            3 | code         | ASC       |  false  |  false
(23 rows)

See also


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