Hi Sreelatha,
The reason is because you are using Aggregation function "SUM" so you need to include GROUP BY clause.
As you have listed PRODUCT_NAME column in your SQL SELECT statement that is not encapsulated in the SQL SUM function, you must use the SQL GROUP BY clause. The PRODUCT_NAME, PRODUCT_ID, REGION_NAME, SUB_REGION_NAME fields must, therefore, be listed in the SQL GROUP BY section.
Regards,
Vivek