The DROP INDEX statement removes indexes from tables.

Synopsis

DROP INDEX IF EXISTS table_name @ index_name , CASCADE RESTRICT

Required Privileges

The user must have the CREATE privilege on each specified table.

Parameters

Parameter Description
IF EXISTS Drop the named indexes if they exist; if they do not exist, do not return an error.
table_name The name of the table with the index you want to drop. Find table names with SHOW TABLES.
index_name The name of the index you want to drop. Find index names with SHOW INDEX.

You cannot drop a table's primary index.
CASCADE Drop all objects (such as constraints) that depend on the indexes.

CASCADE does not list objects it drops, so should be used cautiously.
RESTRICT (Default) Do not drop the indexes if any objects (such as constraints) depend on them.

Examples

Remove an Index (No Dependencies)

> SHOW INDEX FROM tbl;
+-------+--------------+--------+-----+--------+-----------+---------+----------+
| Table |     Name     | Unique | Seq | Column | Direction | Storing | Implicit |
+-------+--------------+--------+-----+--------+-----------+---------+----------+
| tbl   | primary      | true   |   1 | id     | ASC       | false   | false    |
| tbl   | tbl_name_idx | false  |   1 | name   | ASC       | false   | false    |
| tbl   | tbl_name_idx | false  |   2 | id     | ASC       | false   | true     |
+-------+--------------+--------+-----+--------+-----------+---------+----------+
(3 rows)
> DROP INDEX tbl@tbl_name_idx;

> SHOW INDEX FROM tbl;
+-------+---------+--------+-----+--------+-----------+---------+----------+
| Table |  Name   | Unique | Seq | Column | Direction | Storing | Implicit |
+-------+---------+--------+-----+--------+-----------+---------+----------+
| tbl   | primary | true   |   1 | id     | ASC       | false   | false    |
+-------+---------+--------+-----+--------+-----------+---------+----------+
(1 row)

Remove an Index and Dependent Objects with CASCADE

CASCADE drops all dependent objects without listing them, which can lead to inadvertent and difficult-to-recover losses. To avoid potential harm, we recommend dropping objects individually in most cases.
> SHOW INDEX FROM orders;
+--------+---------------------+--------+-----+----------+-----------+---------+----------+
| Table  |        Name         | Unique | Seq |  Column  | Direction | Storing | Implicit |
+--------+---------------------+--------+-----+----------+-----------+---------+----------+
| orders | primary             | true   |   1 | id       | ASC       | false   | false    |
| orders | orders_customer_idx | false  |   1 | customer | ASC       | false   | false    |
| orders | orders_customer_idx | false  |   2 | id       | ASC       | false   | true     |
+--------+---------------------+--------+-----+----------+-----------+---------+----------+
(3 rows)
> DROP INDEX orders@orders_customer_idx;
pq: index "orders_customer_idx" is in use as a foreign key constraint
> SHOW CONSTRAINTS FROM orders;
+--------+---------------------------+-------------+------------+----------------+
| Table  |           Name            |    Type     | Column(s)  |    Details     |
+--------+---------------------------+-------------+------------+----------------+
| orders | fk_customer_ref_customers | FOREIGN KEY | [customer] | customers.[id] |
| orders | primary                   | PRIMARY KEY | [id]       | NULL           |
+--------+---------------------------+-------------+------------+----------------+
> DROP INDEX orders@orders_customer_idx CASCADE;

> SHOW CONSTRAINTS FROM orders;
+--------+---------+-------------+-----------+---------+
| Table  |  Name   |    Type     | Column(s) | Details |
+--------+---------+-------------+-----------+---------+
| orders | primary | PRIMARY KEY | [id]      | NULL    |
+--------+---------+-------------+-----------+---------+


Yes No