CREATE TABLE Transactions_Lots (lot_id VARCHAR2, transaction_id VARCHAR2)
CREATE TABLE TRANSACTIONS (transaction_id VARCHAR2)

Show the average amount of transactions for different lots.
SELECT T2.lot_id, AVG(amount_of_transaction) FROM TRANSACTIONS AS T1 JOIN Transactions_Lots AS T2 ON T1.transaction_id = T2.transaction_id GROUP BY T2.lot_id
SELECT "T2"."lot_id", AVG("amount_of_transaction") FROM "TRANSACTIONS" "T1" JOIN "Transactions_Lots" "T2" ON "T1"."transaction_id" = "T2"."transaction_id" GROUP BY "T2"."lot_id"