>When I specify ORDER BY A_COLUMN DESC NULLS FIRST, the descending index >created on this column is not used and I get 'natural' in plan. >Is there a possibility to use some index when 'nulls first' is specified.
Hi Marcin! I think it may be possible to force using an index, but you have to change your query a bit: With MyCTE1(MyDescOrder, A_Column) As (SELECT 2, A_Column FROM A_Table WHERE A_Column IS NULL), MyCTE2((MyDescOrder, A_Column) As (SELECT 1, A_Column FROM A_Table WHERE A_Column IS NOT NULL) SELECT * FROM MyCTE1 UNION SELECT * FROM MyCTE2 ORDER BY MyDescOrder DESC, A_Column DESC I didn't have any table with descending index to test available, but a similar query with ascending indexes (of course trying to put the NULLS LAST, showed that my index was used. Having said that, I don't know whether this will be any quicker than going NATURAL, and given that it complicates the query a bit, I'd say that even if it did, performance would have to be crucial for you to consider this. Set
