Great! Now, in order to determine what the distance would be if we instead used geometry columns, we need to learn how to convert a geography column to a geometry column.
Basically, all it takes is
::geometry after the column name, but you should also remember about choosing the right SRID.
WHERE name = 'Alaska';
As you can see, we used
ST_Transform. Note that we had to change the SRID from 26910, which was true for San Francisco. The SRID of 3395 can be used for the whole world and has meters as its unit of length. We divided the result by a million to obtain the area of Alaska in square kilometers.