Phantom Reads

Problem

Transaction A runs a count query on orders. Meanwhile, Transaction B inserts a new order and commits. Transaction A runs the count query again and sees a different count. This is a Phantom Read. Write a query that outputs isolation_level with the value: "Phantom reads are prevented by setting the isolation level to Repeatable Read (which locks read ranges) or Serializable."

Database Schema

This problem acts as a scratchpad. You will write your own DDL/DML or conceptual queries, so there is no predefined schema.

Try It

Hint

Solution