CREATE TABLE investors (investor_id NUMBER, investor_details CLOB)
CREATE TABLE transactions (transaction_id NUMBER, investor_id NUMBER, transaction_type_code CLOB, date_of_transaction TIME, amount_of_transaction NUMBER, share_count CLOB, other_details CLOB)
CREATE TABLE lots (lot_id NUMBER, investor_id NUMBER, lot_details CLOB)
CREATE TABLE transactions_lots (transaction_id NUMBER, lot_id NUMBER)
CREATE TABLE ref_transaction_types (transaction_type_code CLOB, transaction_type_description CLOB)
CREATE TABLE sales (sales_transaction_id NUMBER, sales_details CLOB)
CREATE TABLE purchases (purchase_transaction_id NUMBER, purchase_details CLOB)

Show the maximum amount of transaction.
SELECT MAX(amount_of_transaction) FROM transactions
SELECT MAX("amount_of_transaction") FROM "transactions"