CREATE TABLE journal_committee (journal_ID VARCHAR, work_type VARCHAR)
CREATE TABLE journal (sales INT, journal_ID VARCHAR)

What is the average sales of the journals that have an editor whose work type is 'Photo'?
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'
SELECT AVG("T1"."sales") FROM "journal" AS "T1" JOIN "journal_committee" AS "T2" ON "T1"."journal_ID" = "T2"."journal_ID" AND "T2"."work_type" = 'Photo'