how many teams have used the stadium which hosted the judo at the 2008 summer olympics – men's 90 kg ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open dbr_Judo_at_the_2008_Summer_Olympics_–_Men's_90_kg dbp_venue var_x sep_dot var_x dbo_tenant var_uri sep_dot var_x a dbo_Stadium brack_close