CREATE TABLE catalog_structure (catalog_level_name VARCHAR2, catalog_level_number VARCHAR2)
CREATE TABLE catalog_contents (catalog_level_number VARCHAR2, price_in_dollars VARCHAR2)

What is the level name of the cheapest catalog (in USD)?
SELECT t2.catalog_level_name FROM catalog_contents AS t1 JOIN catalog_structure AS t2 ON t1.catalog_level_number = t2.catalog_level_number ORDER BY t1.price_in_dollars LIMIT 1
SELECT "t2"."catalog_level_name" FROM "catalog_contents" "t1" JOIN "catalog_structure" "t2" ON "t1"."catalog_level_number" = "t2"."catalog_level_number" ORDER BY "t1"."price_in_dollars" FETCH FIRST 1 ROWS ONLY