SELECT T2.theme FROM exhibition_record AS T1 JOIN exhibition AS T2 ON T1.exhibition_id  =  T2.exhibition_id WHERE T1.attendance  <  100 INTERSECT SELECT T2.theme FROM exhibition_record AS T1 JOIN exhibition AS T2 ON T1.exhibition_id  =  T2.exhibition_id WHERE T1.attendance  >  500
Show the theme for exhibitions with both records of an attendance below 100 and above 500.
SELECT T2.theme FROM exhibition_record AS T1 JOIN exhibition AS T2 ON T1.exhibition_id = T2.exhibition_id WHERE T1.attendance < 100 INTERSECT SELECT T2.theme FROM exhibition_record AS T1 JOIN exhibition AS T2 ON T1.exhibition_id = T2.exhibition_id WHERE T1.attendance > 500
select t2 . theme from exhibition_record as t1 join exhibition as t2 on t1 . exhibition_id = t2 . exhibition_id where t1 . attendance < value intersect select t2 . theme from exhibition_record as t1 join exhibition as t2 on t1 . exhibition_id = t2 . exhibition_id where t1 . attendance > value
Show the theme for exhibitions with both records of an attendance below 100 and above 500 .