To export only leads with a specific disposition (in this example SALE) from only certain campaigns (in this example 1000, 2000), please log in to PHPMyAdmin and run the following SQL:
select * from vicidial_list where status="SALE" and list_id in (select list_id from vicidial_lists where campaign_id=1000 or campaign_id=2000)
Click on the Export button on the bottom and select the desired format (CSV, SQL…)