rank nation gold silver bronze total
rank
nation
gold
silver
bronze
total
number
first second
number
number
number
number
number text(text) number number number number
1 vietnam (vie) 3 0 3 6
what is the number of countries that had no gold medals ?
WP VBD-AUX DT NN IN NNS WDT VBD-AUX DT NN NNS .
7
select count ( c2 ) from w where c3_number = 0