Table: european_luge_2008
Columns: rank
nation
gold
silver
bronze
total

Question: What is the average number of silver medals for countries with 0 gold and rank under 3?
SQL: SELECT AVG("silver") FROM european_luge_2008 WHERE "gold" = 0 AND "rank" < 3

Question: What is the average gold medals for countries with more than 0 bronze, more than 0 silver, rank over 2 and total over 3?
SQL: SELECT AVG("gold") FROM european_luge_2008 WHERE "bronze" > 0 AND "silver" > 0 AND "rank" > 2 AND "total" > 3