Non-repeatable read in SQL server

A Non-Repeatable Read occurs when a transaction reads the same row twice and gets different values because another transaction modified and committed that row between the two reads. The row itself remains the same, but the data inside the row changes. Non-Repeatable Reads are possible under READ COMMITTED and READ UNCOMMITTED isolation levels. They are prevented by REPEATABLE READ, SNAPSHOT, and SERIALIZABLE isolation levels.

See the demo

Running this query

BEGIN TRAN;  SELECT * FROM Account WHERE AccountNumber='SB100001'

Now we are updating the same record in other session

update Account set Balance=60000.00 WHERE AccountNumber='SB100001'

Record updated successfully.

Now we are running the session 1 read query

We have not do any thing but our query has changed the result. This is called non-repeatable.

Feature	Non-Repeatable Read	Phantom Read
Same Row?	Yes	No
Value Changes?	Yes	Not necessarily
Row Count Changes?	No	Yes
Caused By	UPDATE	INSERT / DELETE
Example	Salary changed	New employee appears