在 oracle sql 中获取时间戳的总和（带小数秒）

Question

您好，我试图找到一种解决方案来对一列中的时间戳求和。我找到了一些帖子，但我认为最终这些解决方案会切断小数秒。

所以我有一个时间戳格式的列，带有 6 个小数秒，例如 '0001-01-01 00:01:23.652148'

我使用此列来保存比赛中的单圈时间。有什么想法吗？ :) 也许我应该使用其他数据类型或格式？

请帮忙！ :) 非常感谢。

Answer 1

使用INTERVAL DAY TO SECOND 类型存储数据，然后使用自定义聚合函数对它们求和。 （但是，如果您必须使用 TIMESTAMP 数据类型，则可以通过减去一个纪元 TIMESTAMP 将其转换为 INTERVAL - 即 TIMESTAMP '0001-01-01 00:00:00.000000）。

SQL Fiddle

Oracle 11g R2 架构设置：

CREATE TABLE LapTimes( time TIMESTAMP(6) )
/

INSERT INTO LapTimes ( time )
SELECT TIMESTAMP '0001-01-01 00:01:23.652148' FROM DUAL UNION ALL
SELECT TIMESTAMP '0001-01-01 00:01:24.123456' FROM DUAL UNION ALL
SELECT TIMESTAMP '0001-01-01 00:01:22.987654' FROM DUAL
/

自定义聚合函数：

CREATE OR REPLACE TYPE IntervalAggregation AS OBJECT(
  value INTERVAL DAY(9) TO SECOND(9),

  STATIC FUNCTION ODCIAggregateInitialize(
    ctx         IN OUT IntervalAggregation
  ) RETURN NUMBER,

  MEMBER FUNCTION ODCIAggregateIterate(
    self        IN OUT IntervalAggregation,
    value       IN     INTERVAL DAY TO SECOND
  ) RETURN NUMBER,

  MEMBER FUNCTION ODCIAggregateTerminate(
    self        IN OUT IntervalAggregation,
    returnValue    OUT INTERVAL DAY TO SECOND,
    flags       IN     NUMBER
  ) RETURN NUMBER,

  MEMBER FUNCTION ODCIAggregateMerge(
    self        IN OUT IntervalAggregation,
    ctx         IN OUT IntervalAggregation
  ) RETURN NUMBER
);
/

CREATE OR REPLACE TYPE BODY IntervalAggregation
IS
  STATIC FUNCTION ODCIAggregateInitialize(
    ctx         IN OUT IntervalAggregation
  ) RETURN NUMBER
  IS
  BEGIN
    ctx := IntervalAggregation( NULL );
    RETURN ODCIConst.SUCCESS;
  END;

  MEMBER FUNCTION ODCIAggregateIterate(
    self        IN OUT IntervalAggregation,
    value       IN     INTERVAL DAY TO SECOND
  ) RETURN NUMBER
  IS
  BEGIN
    IF value IS NULL THEN
      NULL;
    ELSIF self.value IS NULL THEN
      self.value := value;
    ELSE
      self.value := self.value + value;
    END IF;
    RETURN ODCIConst.SUCCESS;
  END;

  MEMBER FUNCTION ODCIAggregateTerminate(
    self        IN OUT IntervalAggregation,
    returnValue    OUT INTERVAL DAY TO SECOND,
    flags       IN     NUMBER
  ) RETURN NUMBER
  IS
  BEGIN
    returnValue := self.value;
    RETURN ODCIConst.SUCCESS;
  END;

  MEMBER FUNCTION ODCIAggregateMerge(
    self        IN OUT IntervalAggregation,
    ctx         IN OUT IntervalAggregation
  ) RETURN NUMBER
  IS
  BEGIN
    IF self.value IS NULL THEN
      self.value := ctx.value;
    ELSIF ctx.value IS NULL THEN
      NULL;
    ELSE
      self.value := self.value + ctx.value;
    END IF;
    RETURN ODCIConst.SUCCESS;
  END;
END;
/

CREATE FUNCTION IntervalSum( value INTERVAL DAY TO SECOND )
RETURN INTERVAL DAY TO SECOND
PARALLEL_ENABLE AGGREGATE USING IntervalAggregation;
/

查询 1：

SELECT IntervalSum( time - TIMESTAMP '0001-01-01 00:00:00.000000' ) AS totalLapTime
FROM   LapTimes

Results：

|    TOTALLAPTIME |
|-----------------|
| 0 0:4:10.763258 |

查询 2：

-- INSERT INTO YOUR_OTHER_TABLE ( TotalLapTime )
SELECT TIMESTAMP '0001-01-01 00:00:00.000000'
       + NUMTODSINTERVAL(
           SUM( 
             EXTRACT( MINUTE FROM time ) * 60
             + EXTRACT( SECOND FROM time )
           ),
           'SECOND'
         ) AS TotalLapTime
FROM   LapTimes

Results：

|            TOTALLAPTIME |
|-------------------------|
| 1-01-01 00:04:10.763258 |