math.sql

select

# this will create a new column using a function 
# this won't be a part of the dataset, just the query itself
# we can calculate the area of the geometry in sq. meters
# then transform that using math to sq. miles
# we can also use a column alias here - as square_miles
# you can call this column anything you want, just change "square_miles"

st_area(state_geom) / 2.59e+6 as square_miles
from
`bigquery-public-data.geo_us_boundaries.states`