SQL查询 - 在12小时内选择重复项

如果我有如下数据

A | 01/01/2008 00:00:00

B | 01/01/2008 01:00:00

A | 01/01/2008 11:59:00

C | 02/01/2008 00:00:00

D | 02/01/2008 01:00:00

D | 02/01/2008 20:00:00

我想只选择标识符(A,B,C或D)在12小时内发生两次的记录.在上面这个例子中,这只是'A'

任何人都可以帮忙(这是针对Oracle数据库)

谢谢

中号

 Select Distinct A.Identifer  
  From Table A
    Join Table B --  EDIT to eliminate self Joins (to same row)
        On A.PrimKey <> B.PrimaryKey
           And A.Identifer = B.Identifer               
           -- EDIT to fix case where 2 at same time
           And A.OccurTime >=  B.OccurTime 
           And A.OccurTime < B.OccurTime + .5

并实施评论中提出的问题,(忽略不同日期的记录)

- 对于SQL Server,

   Select Distinct A.Identifer  
    From Table A
      Join Table B 
        On A.PrimKey <> B.PrimaryKey
           And A.Identifer = B.Identifer
           -- EDIT to fix case where 2 at same time
           And A.OccurTime >= B.OccurTime  
           And A.OccurTime < B.OccurTime + .5
    Where DateDiff(day, A.OccurTime, B.OccurTime) = 0

- 或者是oracle ......

 Select Distinct A.Identifer  
    From Table A
      Join Table B 
        On A.PrimKey <> B.PrimaryKey
           And A.Identifer = B.Identifer
           -- EDIT to fix case where 2 at same time
           And A.OccurTime >= B.OccurTime  
           And A.OccurTime < B.OccurTime + .5
 Where Trunc(A.OccurTime) = Trunc(B.OccurTime)