Database: imdb
Question: How many movies about Persians were released after 1990 ?
SQL:
SELECT COUNT ( DISTINCT t3.title  ) FROM tags AS t2 JOIN keyword AS t1 ON t2.kid  =  t1.id JOIN movie AS t3 ON t2.msid  =  t3.mid WHERE t1.keyword  =  "Persians" AND t3.release_year  >  1990;