如何在 oracle sql 中选择计数值

Question

感谢我的一个朋友，我已经能够获得以下代码，它可以根据 30 分钟的差异计算日期/时间。如果差异小于 30 分钟，则计数保持不变，否则如果大于计数，则增加 1。

SELECT
CASE  
      WHEN DATE2 - LAG(DATE2) over (PARTITION BY NAME, TRUNC(DATE2) ORDER BY DATE2) <= 1 / 48  
        THEN NULL
        ELSE 1
      END AS COUNT1
FROM TABLE1

我忘记要求他包括的是已计为该计数的开始时间和结束时间的值，因为这可以让我计算花费了多长时间，但我不确定如何添加这个基于上面的代码，所以没有尝试任何东西。

如果有人能建议我如何带来这样的东西，我将不胜感激，因为 sql 不是我的强项。

以下是一些示例数据：

NAME | DATE2
Humpty Dumpty | 21-JUL-16 09:27:24
Humpty Dumpty | 21-JUL-16 09:27:24
Humpty Dumpty | 21-JUL-16 09:27:24
Humpty Dumpty | 21-JUL-16 09:27:24
Humpty Dumpty | 21-JUL-16 09:31:31
Humpty Dumpty | 21-JUL-16 09:31:31
Humpty Dumpty | 21-JUL-16 09:31:31
Humpty Dumpty | 21-JUL-16 09:31:31
Humpty Dumpty | 21-JUL-16 16:42:03
Humpty Dumpty | 21-JUL-16 16:42:03
Humpty Dumpty | 21-JUL-16 16:42:03
Humpty Dumpty | 21-JUL-16 16:42:03

当我运行上述查询时，我得到以下信息：

Count1
1
(null)
(null)
(null)
(null)
(null)
(null)
(null)
1
(null)
(null)
(null)

这给了我一个值，但我还需要知道第一个值是什么时候计算的 1，以及计算下一个值之前的最后一个值。

从上面我的结果应该是这样的：

Count1 | Start_time | End_Time
1 | 21-JUL-16 09:27:24 | 21-JUL-16 09:31:31
1 | 21-JUL-16 16:42:03 | 21-JUL-16 16:42:03

需要指出的是，如果半小时内同一日期还有另一个值，那么开始时间也是结束时间..

Answer 1

您想要识别不同的组。因为您使用的是lag() 方法，所以我将继续这样做。下一步是累积和，然后是聚合：

SELECT NAME, TRUNC(DATE2), MIN(DATE2), MAX(DATE2)
FROM (SELECT t1.*,
             SUM(COUNT1) OVER (PARTITION BY NAME, TRUNC(DATE2) ORDER BY DATE2) as grp
      FROM (SELECT t1.*,
                   (CASE WHEN DATE2 - LAG(DATE2) over (PARTITION BY NAME, TRUNC(DATE2) ORDER BY DATE2) <= 1/48  
                         THEN 0 ELSE 1
                    END) AS COUNT1
            FROM TABLE1 t1
           ) t1
      ) t1
GROUP BY NAME, TRUNC(DATE2), grp;

Answer 2

DATE2

是当前行的时间 - 在计算中这是结束时间

LAG(DATE2) over (PARTITION BY NAME, TRUNC(DATE2) ORDER BY DATE2)

是前一行的时间（按日期排序） - 在计算中这是开始时间

真的就这么简单。

我已更新以下内容以（希望）符合您更新后的要求。

查询 A 使用 LAG 和 LEAD 函数来确定每一行是位于一组条目的开头（前一行相差 > 30 分钟）还是一组条目的末尾（下一行相差 > 30 分钟）

然后查询 B 限制结果行是开始行或结束行（其他一切都只是噪音）

最后每个开始和结束都连接在一起成为一行。

WITH
 test_data (name, date2) AS
  (SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:27:24','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:27:24','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:27:24','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:27:24','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:31:31','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:31:31','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:31:31','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:31:31','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:40:00','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 09:40:00','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 16:42:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 16:42:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 16:42:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 16:45:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 16:45:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 18:00:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 18:00:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'Humpty Dumpty',TO_DATE('21/07/2016 18:00:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'ABC',TO_DATE('21/07/2016 18:00:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'ABC',TO_DATE('21/07/2016 18:10:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'ABC',TO_DATE('21/07/2016 18:50:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL UNION ALL
   SELECT 'ABC',TO_DATE('21/07/2016 18:51:03','DD/MM/YYYY HH24:MI:SS') FROM DUAL
 )
SELECT
 name
,TO_CHAR(start_time,'DD/MM/YYYY HH24:MI:SS')     start_time
,TO_CHAR(end_time,'DD/MM/YYYY HH24:MI:SS')       end_time
FROM
 --Query B
 (SELECT
   name
  ,date2                                      start_time
  ,LEAD(date2) OVER (PARTITION BY name,TRUNC(date2) ORDER BY date2)   end_time
  ,start_flag
  FROM
   --Query A
   (SELECT
     name
    ,date2
    ,CASE
      WHEN date2 - LAG(date2) OVER (PARTITION BY name, TRUNC(date2) ORDER BY date2) <= (1/48)
       THEN 'N'
      ELSE 'Y'
     END                                        start_flag
    ,CASE
      WHEN LEAD(date2) OVER (PARTITION BY name, TRUNC(date2) ORDER BY date2) - date2 <= (1/48)
       THEN 'N'
      ELSE 'Y'
     END                                        end_flag
    FROM
     test_data
    ORDER BY
     name
    ,date2
   )
  WHERE 1=1
  AND (start_flag = 'Y' OR end_flag = 'Y')
  )
WHERE start_flag = 'Y'
;