Get the top row after order by in Oracle Subquery

database, limit, oracle, oracle10g, sql

Solution

try this one

select * from
  (SELECT id, name, department, age, score,
  ROW_NUMBER() OVER (partition by department order by age desc, score asc) srlno 
  FROM student) 
where srlno = 1;

Problem

I have a table student(id, name, department, age, score). I want to find the youngest student who has the highest(among the youngest students) score of each department. In SQL Server, I can use following SQL. ``` select * from student s1 where s1.id in (select s2.id from student s2 where s2.department = s1.department order by age asc, score desc top 1). ``` However, in Oracle, you cannot use the order by clause in subquery and there is no limit/top like keyword. I have to join the student table with itself two times to query the result. In oracle, I use following SQL. ``` select s1.* from student s1, (select s2.department, s2.age, max(s2.score) as max_score from student s2, (select s3.department, min(s3.age) as min_age from student s3 group by s3.department) tmp1 where s2.department = tmp1.department and s2.age = tmp1.min_age group by s2.department, s2.age) tmp2 where s1.department =tmp2.department and s1.age = tmp2.age and s1.score=tmp2.max_score ``` Does anyone have any idea to simplify the above SQL for oracle.

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