Table: portland_tallest_buildings
Columns: name
street_address
years_as_tallest
height_feet_m
floors

Question: What's the least amount of floors at 921 sw sixth avenue?
SQL: SELECT MIN("floors") FROM portland_tallest_buildings WHERE "street_address" = '921 sw sixth avenue'

Question: What's the address of the union bank of California tower?
SQL: SELECT "street_address" FROM portland_tallest_buildings WHERE "name" = 'union bank of california tower'

Question: What were the years that the building at 200 sw harrison was considered to be the tallest building?
SQL: SELECT "years_as_tallest" FROM portland_tallest_buildings WHERE "street_address" = '200 sw harrison'