Database: imdb
Question: Which producer has worked with the most number of directors ?
SQL: select t1.name from director as t3 join directed_by as t2 on t3.did  =  t2.did join movie as t4 on t4.mid  =  t2.msid join made_by as t5 on t4.mid  =  t5.msid join producer as t1 on t1.pid  =  t5.pid group by t1.name order by count ( distinct t3.name  ) desc limit 1;