What is a non-repeatable read?

What is a non-repeatable read?

A Non-repeatable read is where one transaction cannot read the second time unless another transaction alters the row.

This problem can be solved by setting the transaction isolation level to TRANSACTION_REPEATABLE_READ.

What is a non-repeatable read? What is phantom read?

Non-repeatable read

While performing select statement, non-repeatable reads may occur when read locks are not acquired. Non-repeatable reads may occur at the need of effected transaction by a commit conflict, must roll back is relaxed.

Phantom read

At the time of execution of a transaction, if two queries that are identical are executed, and the rows returned are different from one another, it is stated that a phantom read occurred. The possibility of occurring phantom reads is when the range locks are not acquired by the execution of SELECT.