Table: canoe_world_champs_1979
Columns: rank
nation
gold
silver
bronze
total

Question: How many silver medals did spain have when they had more than 0 bronze medals and less than 54 total medals?
SQL: SELECT "silver" FROM canoe_world_champs_1979 WHERE "bronze" > 0 AND "total" < 54 AND "nation" = 'spain'

Question: What was the highest number of gold medals when there were 0 silver medals?
SQL: SELECT MAX("gold") FROM canoe_world_champs_1979 WHERE "silver" < 0