Upgraded from 4.7.17 to 4.7.21 and got the following message that I don't know how to fix. I don't have drush and the other answers to this problem don't include this index or don't fix this particular problem. I tried "ALTER TABLE civicrm_financial_type DROP INDEX index_entity_id_entity_table_account_relationship" but MySQL can't do it and says 'check that column/key exists'. Also tried 'ALTER TABLE civicrm_entity_financial_account DROP INDEX index_entity_id_entity_table_account_relationship' with the same result
Operation failed: Update Indices DB Error: already exists Debug information: CREATE UNIQUE INDEX index_entity_id_entity_table_account_relationship ON civicrm_entity_financial_account (entity_id, entity_table, account_relationship) [nativecode=1062 ** Duplicate entry '5-civicrm_financial_type-3' for key 'index_entity_id_entity_table_account_relationship']