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;