sql - 別の列に基づいて時間差を計算し、合計する

Question

次のようなデータを含むテーブルがあります

ReferenceNo                 CommentDate             StepName            Originator  StartTime
1   CHQRCL/0083/2013/FEB    2013-02-25 15:20:07.000 Initiate Process    P8Admin 2013-02-25 15:20:07.000
1   CHQRCL/0083/2013/FEB    2013-02-25 15:20:44.000 Finance Controller  P8Admin 2013-02-25 15:20:07.000
1   CHQRCL/0083/2013/FEB    2013-02-25 15:21:52.000 Originator  P8Admin 2013-02-25 15:20:07.000
1   CHQRCL/0083/2013/FEB    2013-02-25 15:23:26.000 Finance Controller  P8Admin 2013-02-25 15:20:07.000
1   CHQRCL/0083/2013/FEB    2013-02-25 15:23:55.000 Finance Officer P8Admin 2013-02-25 15:20:07.000
2   CHQRCL/0089/2013/FEB    2013-02-25 15:43:48.000 Initiate Process    P8Admin 2013-02-25 15:43:48.000
2   CHQRCL/0089/2013/FEB    2013-02-25 15:43:59.000 Finance Controller  P8Admin 2013-02-25 15:43:48.000
2   CHQRCL/0089/2013/FEB    2013-02-25 15:44:11.000 Asset GM    P8Admin 2013-02-25 15:43:48.000
3   CHQRCL/0093/2013/MAR    2013-03-06 16:19:05.000 Initiate Process    P8Admin 2013-03-06 16:19:05.000
3   CHQRCL/0093/2013/MAR    2013-03-06 16:21:57.000 Finance Controller  P8Admin 2013-03-06 16:19:05.000
3   CHQRCL/0093/2013/MAR    2013-03-06 16:23:55.000 Asset GM    P8Admin 2013-03-06 16:19:05.000
3   CHQRCL/0093/2013/MAR    2013-03-06 16:24:09.000 CFO P8Admin 2013-03-06 16:19:05.000
3   CHQRCL/0093/2013/MAR    2013-03-06 16:24:19.000 CEO P8Admin 2013-03-06 16:19:05.000
3   CHQRCL/0093/2013/MAR    2013-03-06 16:24:40.000 Finance Officer P8Admin 2013-03-06 16:19:05.000
4   CHQRCL/0094/2013/MAR    2013-03-06 16:58:47.000 Initiate Process    P8Admin 2013-03-06 16:58:47.000
4   CHQRCL/0094/2013/MAR    2013-03-06 17:00:45.000 Finance Controller  P8Admin 2013-03-06 16:58:47.000
4   CHQRCL/0094/2013/MAR    2013-03-06 17:00:54.000 Asset GM    P8Admin 2013-03-06 16:58:47.000
4   CHQRCL/0094/2013/MAR    2013-03-06 17:04:48.000 CFO P8Admin 2013-03-06 16:58:47.000
4   CHQRCL/0094/2013/MAR    2013-03-06 17:05:06.000 CEO P8Admin 2013-03-06 16:58:47.000
4   CHQRCL/0094/2013/MAR    2013-03-06 17:05:35.000 Finance Officer P8Admin 2013-03-06 16:58:47.000
5   CHQRCL/0108/MAR/2013    2013-03-10 08:58:22.000 Initiate Process    Mohamed Ubaid   2013-03-10 08:58:22.000
5   CHQRCL/0108/MAR/2013    2013-03-10 09:06:23.000 Finance Controller  Mohamed Ubaid   2013-03-10 08:58:22.000
5   CHQRCL/0108/MAR/2013    2013-03-10 09:07:06.000 Finance Officer Mohamed Ubaid   2013-03-10 08:58:22.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:26:10.000 Initiate Process    Allan C Fampulme    2013-03-10 09:26:10.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:32:34.000 Finance Controller  Allan C Fampulme    2013-03-10 09:26:10.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:33:22.000 Asset GM    Allan C Fampulme    2013-03-10 09:26:10.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:35:39.000 Originator  Allan C Fampulme    2013-03-10 09:26:10.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:36:06.000 Asset GM    Allan C Fampulme    2013-03-10 09:26:10.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:36:20.000 CFO Allan C Fampulme    2013-03-10 09:26:10.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:36:41.000 CEO Allan C Fampulme    2013-03-10 09:26:10.000
6   CHQRCL/0110/MAR/2013    2013-03-10 09:37:34.000 Finance Officer Allan C Fampulme    2013-03-10 09:26:10.000

まず、参照番号ごとに各ステ​​ップにかかる時間（つまり、参照番号1のFinance Controllerの場合は37秒かかりました）が必要です。平均を計算したい（例と同じFinanceControllerの手順を実行します。1refNoで7秒+1refNoでもう一度94秒+2refNo +で11秒など）DIVIDED BY 6）

Answer 1

問題を解決する次のクエリを使用しました。WITHCTEAS

（
SELECT ROW_NUMBER（）OVER（PARTITION BY ReferenceNo ORDER BY CommentDate）As RowNum、*
FROM FNCUSTOM.dbo.WorkflowHistory T
）

SELECT ReferenceNo、StepName、CommentDate、DiffDays = DATEDIFF（ s、（SELECT CommentDate FROM CTE c2 WHERE c2.ReferenceNo = CTE.ReferenceNo AND c2.RowNum = CTE.RowNum-1）、CommentDate）/ 60.0 / 60.0 / 24.0
FROM CTE