Java 函数结果作为类字段值

我有PostgreSQL数据库，其中有一个函数

month\u traffic（）

是否可以将postgresql函数的结果设置为monthMBytes的字段值

// month traffic
@Formula("(select month_traffic(hst_pcode)")
private transient float monthMBytes = 0;

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致以最良好的祝愿。

我阅读了相关的SO问题、一些文档和

我需要使磁场非瞬态

我不需要场地设置员。只有getter enought

在@Formula注释中，我编写了从函数中选择值的sql查询

PostgreSQL函数必须返回非空值

所以，我的新功能是

CREATE OR REPLACE FUNCTION month_traffic(hostcode int) RETURNS numeric(14,2) AS $$
DECLARE
  begin_date date := CAST((EXTRACT(year FROM now()) || '-' || EXTRACT(month FROM now()) || '-' || '01') AS date);
  end_date date := CAST((EXTRACT(year FROM now()) || '-' || EXTRACT(month FROM now()) + 1 || '-' || '01') AS date);
  result numeric(14,2) := 0;
BEGIN
  result := (SELECT SUM(day_mbytes) FROM daily 
    WHERE (day_hstcode = hostcode) AND (day_date >= begin_date) AND (day_date < end_date));
  IF (result IS NULL) THEN
    result := 0;
  END IF;
  RETURN result;
END;
$$ LANGUAGE plpgsql

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现在一切正常。谢谢您的链接和评论。

谢谢您的链接。我读了之后感到困惑——在

@formula

注释中是HQL还是原生SQL。我所需要的就是去尝试。

// month traffic
@Formula("(select month_traffic(hst_pcode)")
private transient float monthMBytes = 0;

CREATE OR REPLACE FUNCTION month_traffic(hostcode int) RETURNS numeric(14,2) AS $$
DECLARE
  begin_date date := CAST((EXTRACT(year FROM now()) || '-' || EXTRACT(month FROM now()) || '-' || '01') AS date);
  end_date date := CAST((EXTRACT(year FROM now()) || '-' || EXTRACT(month FROM now()) + 1 || '-' || '01') AS date);
  result numeric(14,2) := 0;
BEGIN
  result := (SELECT SUM(day_mbytes) FROM daily 
    WHERE (day_hstcode = hostcode) AND (day_date >= begin_date) AND (day_date < end_date));
  IF (result IS NULL) THEN
    result := 0;
  END IF;
  RETURN result;
END;
$$ LANGUAGE plpgsql

  . . .
  @Formula("(select month_traffic(hst_pcode))")
  private float monthMBytes;

  public float getMonthMBytes() {
    return monthMBytes;
  }
  . . .