Question

How do you drop an index only if it exists?

It seems simple but I did found anything on the net.
The idea is to drop it only if it exists, because if not, I will have an error and my process stops.

I found this to find if the index exists:

select index_name
from user_indexes
where table_name = 'myTable'
and index_name='myIndexName'

But I don’t know how to put it together with

DROP INDEX myIndexName

Answer 1

DECLARE
   COUNT_INDEXES   INTEGER;
BEGIN
   SELECT COUNT ( * )
     INTO COUNT_INDEXES
     FROM USER_INDEXES
    WHERE INDEX_NAME = 'myIndexName';
   -- Edited by UltraCommit, October 1st, 2019
   -- Accepted answer has a race condition.
   -- The index could have been dropped between the line that checks the count
   -- and the execute immediate
   IF COUNT_INDEXES > 0
   THEN
      EXECUTE IMMEDIATE 'DROP INDEX myIndexName';
   END IF;
END;
/