如何从报告中删除重复的列值

Question

从这：

Hotel                     Type   Room Guest                                     From      To
    ------------------------- ------ ---- ----------------------------------------- --------- ---------
    University Inn & Suites   Double 101  George Brown                              11-SEP-10 14-SEP-10
    University Inn & Suites   Double 101  George Brown                              11-OCT-10 13-OCT-10
    University Inn & Suites   Double 102
    University Inn & Suites   Double 103
    University Inn & Suites   Double 104
    University Inn & Suites   Double 105
    University Inn & Suites   Family 106  George Brooks                             22-SEP-10 27-SEP-10
    University Inn & Suites   Family 107
    University Inn & Suites   Single 201  Sandra Williams                           15-SEP-10 19-SEP-10
    University Inn & Suites   Single 201  Liz Armstrong                             16-SEP-10 18-SEP-10
    University Inn & Suites   Single 201  Craig Harper                              19-SEP-10 22-SEP-10
    University Inn & Suites   Single 202  Roger Harris                              03-SEP-10 10-SEP-10
    University Inn & Suites   Single 202  Tonya Harris                              23-SEP-10 27-SEP-10
    University Inn & Suites   Single 203
    University Inn & Suites   Single 204
    University Inn & Suites   Single 205

到这

    Hotel                     Type   Room Guest                                     From      To
    ------------------------- ------ ---- ----------------------------------------- --------- ---------
    University Inn & Suites   Double 101  George Brown                              11-SEP-10 14-SEP-10
                                          George Brown                              11-OCT-10 13-OCT-10
                                     102  
                                     103
                                     104
                                     105
                              Family 106  George Brooks                             22-SEP-10 27-SEP-10
                                     107
                              Single 201  Sandra Williams                           15-SEP-10 19-SEP-10
                                     201  Liz Armstrong                             16-SEP-10 18-SEP-10
                                          Craig Harper                              19-SEP-10 22-SEP-10
                                     202  Roger Harris                              03-SEP-10 10-SEP-10
                                          Tonya Harris                              23-SEP-10 27-SEP-10
                                     203
                                     204
                                     205

Answer 1

这是您显示的表格结构（还是）报告的结果？

我的猜测是它是 SQLPLUS 报告的结果。如果是这种情况，并且您希望酒店名称出现一次（直到其更改），您可以指定

Break on hotel;

Select hotel, type, room_guest
  from hotels
  order by hotel;

以达到所需的结果。

如果是结构，则无法删除除第一行之外的所有列值。 （事实上​​，就数据库而言，没有什么比第一行更好的了）。如果您想消除重复数据，请考虑规范化您的表。

http://en.wikipedia.org/wiki/Database_normalization\

请发布表说明和工具（如果有），以便您获得适合您案例的答案。

Answer 2

使用 lag 访问前一行并检查它是否与当前行具有相同的值怎么样？

select decode(hotel,
              lag(hotel, 1, null) over (order by hotel, room, ...), null,
              hotel) as "Hotel"
  from ...