Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE artist ( artist_id number, name text, country text, year_join number, age number )
TABLE: CREATE TABLE exhibition ( exhibition_id number, year number, theme text, artist_id number, ticket_price number )
TABLE: CREATE TABLE exhibition_record ( exhibition_id number, date text, attendance number )

### Question ###
Which themes have had corresponding exhibitions that have had attendance both below 100 and above 500?

### Accurate SQL ###

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