使用SQL查詢從單列設置兩個列值

Question

我有一張桌子，上面有以下細節

ID    statusID  logTime
100238  1   2011-07-07 03:48:43.000
100238  2   2011-07-07 03:48:46.000
100238  1   2011-07-07 09:07:57.000
100238  2   2011-07-07 16:12:28.000
100238  1   2011-07-08 02:59:57.000
100238  2   2011-07-08 03:00:00.000
100238  1   2011-07-08 09:26:37.000
100238  2   2011-07-08 14:03:05.000

和所需的輸出應該像

repID   ClockIn                    ClockOut
100238  2011-07-07 03:48:43.000    2011-07-07 03:48:46.000
100238  2011-07-07 09:07:57.000    2011-07-07 16:12:28.000
100238  2011-07-08 02:59:57.000    2011-07-08 03:00:00.000
100238  2011-07-08 09:26:37.000    2011-07-08 14:03:05.000

即..如果statusID為1，則日志時間必須在ClockIn列中；如果statusID為2，則日志時間必須在ClockOut列中

我已經使用過類似的查詢

SELECT repID,
       ClockIn,
       ClockOut from
  (SELECT a.eventID, 
          a.repID, 
          a.logTime, 
          CASE WHEN a.statusID = 1 THEN a.logTime ELSE NULL END AS ClockIn, 
          CASE WHEN b.statusID = 2 THEN b.logTime ELSE NULL END AS ClockOut
   FROM tbl_ets_reptimelog a
   LEFT JOIN tbl_ets_reptimelog b ON a.repID = b.repID)c

結果像

repID   ClockIn                     ClockOut
100238  2011-07-07 03:48:43.000     NULL
100238  2011-07-07 03:48:43.000     2011-07-07 03:48:46.000
100238  2011-07-07 09:07:57.000     NULL
100238  2011-07-07 09:07:57.000     2011-07-07 16:12:28.000
100238  2011-07-08 02:59:57.000     NULL
100238  2011-07-08 02:59:57.000     2011-07-08 03:00:00.000
100238  2011-07-08 09:26:37.000     NULL
100238  2011-07-08 09:26:37.000     2011-07-08 14:03:05.000

如何刪除ClockOut列中出現NULL值的多余行

請幫助擺脫這個問題......

Answer 1

只需在外部查詢中添加WHERE子句

select repID,ClockIn,ClockOut from(select a.eventID, a.repID, a.logTime, 
case when a.statusID = 1 then a.logTime else null end as ClockIn,  
case when b.statusID = 2 then b.logTime else null end as ClockOut from tbl_ets_reptimelog a 
left join tbl_ets_reptimelog b on a.repID = b.repID)c
WHERE ClockOut IS NOT NULL

Answer 2

此查詢應返回所需的結果：

SELECT
  t1.ID,
  t1.logTime check_in,
  CASE WHEN MIN(t2.logTime) < MIN(t3.logTime) OR MIN(t3.logTime) IS NULL
       THEN MIN(t2.logTime) END check_out
FROM
  Logs t1 LEFT JOIN Logs t2
  ON t1.ID = t2.ID
     AND t2.statusID=2
     AND t1.logTime<t2.logTime
  LEFT JOIN Logs t3
  ON t2.ID = t3.ID
     AND t3.statusID=1
     AND t1.logTime<t3.logTime
WHERE
  t1.statusID=1
GROUP BY
  t1.ID, t1.logTime

請看這里的小提琴。