select state_name, tax_rate*100 as tax_rate_in_percent, case when shipping_p = 't' then 'Yes' else 'No' end as shipping_p
from ec_sales_tax_by_state, us_states
where ec_sales_tax_by_state.usps_abbrev = us_states.abbrev
select usps_abbrev from ec_sales_tax_by_state