CREATE TABLE TRANSACTIONS (investor_id VARCHAR2, transaction_type_code VARCHAR2)

Show the number of transactions with transaction type code 'SALE' for different investors if it is larger than 0.
SELECT investor_id, COUNT(*) FROM TRANSACTIONS WHERE transaction_type_code = "SALE" GROUP BY investor_id
SELECT "investor_id", COUNT(*) FROM "TRANSACTIONS" WHERE "SALE" = "transaction_type_code" GROUP BY "investor_id"