Spring Data JPA sort by calculated fields - jpa

Question

I have an entity which contains the data for the run - date, distance, duration and some additional:
#Entity
class RunEntry {
private Long id;
private LocalDate date;
private int weekNo;
private Long distance;
private Duration duration;
private Long userId;
// getters, setters
}
Based on this data I have to create a report which will contain per week distance and average speed (that's why I added weekNo column to easily group by):
class AverageWeekRun {
private LocalDate weekStart;
private LocalDate weekEnd;
private BigDecimal averageSpeed;
private Long distance;
// getters, setters
}
To achieve this I create a Spring Data JPA projection which contains weekNo, sum of distance and sum of duration:
interface RunPerWeek {
int getWeekNo();
Long getSumOfDistance();
Long getSumOfDuration();
}
and I created a simple method in repository:
#Query("select r.weekNo as weekNo, sum(r.distance) as sumOfDistance, sum(r.duration) as sumOfDuration "
+ "from RunEntry r where r.userId = :userId group by r.weekNo")
Page<RunPerWeek> findRunPerWeekForUser(Long userId, Pageable pageable)
It works fine, I can use this query result and map it to AverageWeekRun (by calculating the week start/end based on weekNo and average speed based on sum of distance and sum of duration).
However, I want to use sort from pageable to order by average speed or by week start or week end date. These fields are calculate so I get an exception when I try to pass it with sort. How can it be solved? I want the user to use field names from AverageWeekRun class but some of them are calculated and Spring Data JPA cannot handle it.

Answer 1

You can use:
Sort sort = Sort.by(Sort.Direction.DESC, "sumOfDistance");
Pageable pageable = PageRequest.of(page, limit, sort);
I have used it, as long as your calculated value has "as somename", this will work.