Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:

Convert text to sql: Which themes have had corresponding exhibitions that have had attendance both below 100 and above 500? | artist : artist_id , name , country , year_join , age | exhibition : exhibition_id , year , theme , artist_id , ticket_price | exhibition_record : exhibition_id , date , attendance | exhibition.artist_id = artist.artist_id | exhibition_record.exhibition_id = exhibition.exhibition_id | 

### Response:

select _ from _ where _ intersect select _ from _ where _ | select exhibition.theme from exhibition_record join exhibition on exhibition_record.exhibition_id = exhibition.exhibition_id where exhibition_record.attendance < 100 intersect select exhibition.theme from exhibition_record join exhibition on exhibition_record.exhibition_id = exhibition.exhibition_id where exhibition_record.attendance > 500