计算两个坐标之间的距离 SQL + Criteria Builder

Question

所以在我的代码中，我希望能够使用一些参考坐标检查哪些坐标在范围内。 一开始我使用的是一些本机 SQL 查询，例如：

  @Query(
          value = "SELECT * FROM event " +
                  "   inner join event_location location on location.id = event.location_id\n" +
                  "  where Round( ST_Distance_Sphere(\n" +
                  "    Point(?1 , ?2 )," +
                  "    Point(location.longtitude , location.latitude ), 4326), 2) <= ?3",
          nativeQuery = true)
  List<Event> findAllEventsInRange(double longtitude, double latitude, String range);

它工作得很好，但现在我想将规范与标准构建器一起使用。 老实说，我不知道如何在 where 关键字之后写条件。

谁能让我知道我该怎么做？

编辑：实体已定义。 而且我已经创建了现在加入两个表的规范 - 事件和事件位置：

public static Specification<Event> filter(Search search){
return (root, cq, cb) -> {
      Predicate location = null;

      List<Predicate> result = new ArrayList<>();

      if(search.getLat() != null && search.getLng() != null && search.getRange() != null) {
         Join<Event,EventLocation> join = root.join("eventLocation", JoinType.LEFT);
            }

            return cb.and(result.toArray(new Predicate[result.size()]));
        };
    }

现在我需要创建一个正确的谓词，它将与 WHERE 之后的语句执行相同的操作。 I know there is function on criteria builder which can be used for some native sql function but not sure how i can use it in my case and combine with different other sql functions as well.

Answer 1

为此，您需要使用通用的 function 调用语法，如下所示：

public static Specification<Event> filter(Search search){
    return (root, cq, cb) -> {
      Predicate location = null;

      List<Predicate> result = new ArrayList<>();

      if(search.getLat() != null && search.getLng() != null && search.getRange() != null) {
         Join<Event,EventLocation> join = root.join("eventLocation", JoinType.LEFT);
         result.add(
           cb.le(
             cb.function("Round", String.class,
               cb.function("ST_Distance_Sphere", String.class, 
                 cb.function("Point", String.class, 
                   cb.literal(search.getLat()),
                   cb.literal(search.getLng())
                 ),
                 cb.function("Point", String.class, 
                   join.get("longtitude"),
                   join.get("latitude ")
                 ),
                 cb.literal(4326)
               ),
               cb.literal(2)
             ),
             cb.literal(search.getRange())
           )
         );
      }
  
      return cb.and(result.toArray(new Predicate[result.size()]));
   };
}