What are the dates of transactions with amount smaller than 3000?
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
What are the transaction type codes of those?
select t2.transaction_type_code from sales as t1 join transactions as t2 on t1.sales_transaction_id = t2.transaction_id where t2.amount_of_transaction < 3000