Oracle query to fetch the previous value of a related row in same table - oracle

Question

I have a table Student which has name and ratings year wise.
Name Year Rating
Ram 2016 10
Sam 2016 9
Ram 2014 8
Sam 2012 7
I need to find the previous rating of the employee which could be last year or some years before.
The query should return below results
Name Cur_rating_year_2016 Prev_rating
Ram 10 8
Sam 9 7
Below is the script for insert and create
Create table Student (name varchar2(10), year number, rating number );
insert into student values('Ram' ,2016 ,10);
insert into student values('Sam' ,2016 ,9);
insert into student values('Sam' ,2012 ,7);
insert into student values('Ram' ,2014 ,8);
Is there a way to achieve this using select query?

Answer 1

Use LAG analytical function https://docs.oracle.com/database/122/SQLRF/LAG.htm#SQLRF00652
LAG is an analytic function. It provides access to more than one row
of a table at the same time without a self join. Given a series of
rows returned from a query and a position of the cursor, LAG provides
access to a row at a given physical offset prior to that position.
For the optional offset argument, specify an integer that is greater
than zero. If you do not specify offset, then its default is 1. The
optional default value is returned if the offset goes beyond the scope
of the window. If you do not specify default, then its default is
null.
SELECT stud_name AS name,
r_year AS year,
r_value AS rating,
lag(r_value, 1, NULL) OVER(PARTITION BY stud_name ORDER BY r_year) AS prev_rating
FROM stud_r
ORDER BY stud_name;

Answer 2

Try as:
SELECT A.NAME,A.RATING,B.RATING FROM
STUDENTS A INNER JOIN STUDENTS B
ON A.NAME=B.NAME
WHERE A.YEAR='2016' AND B.YEAR<>'2016'
ORDER BY A.NAME ASC