CREATE TABLE journal_committee (journal_ID VARCHAR(255), work_type VARCHAR(255)); CREATE TABLE journal (sales INTEGER, journal_ID VARCHAR(255))
What is the average sales of the journals that have an editor whose work type is 'Photo'?
    
SQL: SELECT AVG(T1.sales) FROM journal AS T1 JOIN journal_committee AS T2 ON T1.journal_ID = T2.journal_ID WHERE T2.work_type = 'Photo'