DROP INDEX deletes an index.
Only the owner of an index or a system administrator can run DROP INDEX command.
DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] index_name [, ...] [ CASCADE | RESTRICT ];
Deletes an index without locking it. In general, during the deletion, the access of other statements to the tables that the index depends on is blocked. This keyword allows the access of other statements in this case.
This option only specifies one index name, and CASCADE cannot be used in this case.
The DROP INDEX command can be run within a transaction, but DROP INDEX CONCURRENTLY cannot be run in a transaction.
Sends a notice instead of an error if the specified index does not exist.
Specifies the name of the index to be deleted.
Value range: An existing index.
See Example in CREATE INDEX.