when did the transactions that were less that 3000 occur?
SELECT T2.date_of_transaction FROM SALES AS T1 JOIN TRANSACTIONS AS T2 ON T1.sales_transaction_id  =  T2.transaction_id WHERE T2.amount_of_transaction < 3000
transactions that were less than 3000 refers to amount_of_transaction < 3000; when did the transactions occur refers to date_of_transaction;