Removing duplicate entries from driver tables enables ``++OPEN SQL++`` to generate fewer queries for getting the same data, giving a performance boost.


== Noncompliant Code Example

----
SELECT carrid , connid , seatsocc FROM flights
INTO TABLE seatsocc_tab
FOR ALL ENTRIES IN conn_tab
WHERE carrid = conn_tab-carrid
AND connid = conn_tab-connid.
----


== Compliant Solution

----
SORT conn_tab BY carrid.
DELETE ADJACENT DUPLICATES FROM conn_tab COMPARING carrid.
...
SELECT carrid , connid , seatsocc FROM flights
INTO TABLE seatsocc_tab
FOR ALL ENTRIES IN conn_tab
WHERE carrid = conn_tab-carrid
AND connid = conn_tab-connid.
----

