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, states
where ec_sales_tax_by_state.usps_abbrev = states.usps_abbrev
select usps_abbrev from ec_sales_tax_by_state