How to use row_number

I need to create a Unique ID in View which is not available in Table.

I searched many places but all told to use row_number. Even though i tried but its throwing an error:

Have used this  SELECT Row_number() OVER(ORDER BY `locationName`) AS `RID`,

Note: `locationName` is available as column and have used in the view that have created

Can someone help out with workable code