如何通过Query dsl NumberExpression列进行排序

Question

在 mariadb 中，我创建了计算用户点和地点点之间距离的函数

    /* create function */
    DELIMITER $$

    CREATE
    FUNCTION `u_st_distance_sphere`(`user_point` POINT, `place_point` POINT)
    RETURNS double
    BEGIN
    return (6371*acos(cos(radians(ST_X(user_point)))*cos(radians(ST_X(place_point)))*cos(radians(ST_Y(place_point))
        -radians(ST_Y(user_point)))+sin(radians(ST_X(user_point)))*sin(radians(ST_X(place_point)))));
    END$$
    DELIMITER ;

要使用该函数，请在 CustomDialect 类中注册函数并在 .yml 中应用

public class MariadbCustomDialect extends MariaDB103Dialect {
    public MariadbCustomDialect() {
        super();
        this.registerFunction(
                "u_st_distance_sphere",
                new StandardSQLFunction("u_st_distance_sphere", StandardBasicTypes.DOUBLE)
        );
    }
}

spring:
  ...
  jpa:
    ...
    database-platform: ...global.config.MariadbCustomDialect

我想制作用点计算的距离列并按距离升序排序

//in PlaceCustomRepository
//making filtered JPQLQuery

String pointWKT = String.format("POINT(%s %s)", 
                                 placeFilterParam.getLatitude(),
                                 placeFilterParam.getLongitude());

NumberTemplate<Double> expr = Expressions.numberTemplate(
    Double.class, 
    "u_st_distance_sphere( ST_GeomFromText({0}), ST_GeomFromText({1}) )", 
    pointWKT, 
    place.point);

JPQLQuery<PlaceResponseTest> query = jpaQueryFactory
    .select(
            new QPlaceResponseTest(place.id, 
                                   expr.as("distance")))
    .from(place)
    .orderBy();

如何指定距离列？

谢谢

Answer 1

我发现使用常量表达式可以工作

JPQLQuery<PlaceResponseTest> query = jpaQueryFactory
    .select(
            new QPlaceResponseTest(place.id, 
                                   expr.as("distance")))
    .from(place)
    .orderBy(new OrderSpecifier<>(Order.ASC, Expressions.constant("distance")));