麻烦问下，有下列一组数据怎么抽取该表里面时间字段是连续三天的用户

Question

用户id 时间
32454 2012-2-3
32454 2012-2-4
32454 2012-2-12
32454 2012-2-13
32454 2012-2-14
32454 2012-2-15
32454 2012-2-16
32454 2012-2-17
32454 2012-2-18
32454 2012-4-10
32454 2012-4-11
8000000003 2012-4-11
8000000005 2012-1-5
8000000006 2012-4-11
8000000014 2012-1-18
8000000035 2012-4-10
8000000035 2012-4-11
8000000044 2012-2-18
8000000045 2012-2-17
8000000045 2012-2-18
8000000050 2012-2-17
8000000050 2012-2-18
8000000052 2012-2-14
8000000052 2012-2-15
8000000052 2012-2-16
8000000052 2012-2-17
8000000053 2012-2-15
8000000060 2012-2-25
8000000060 2012-2-28
8000000060 2012-2-29
8000000060 2012-3-1
8000000060 2012-3-2
8000000060 2012-3-3
8000000060 2012-3-7
8000000060 2012-3-8
8000000061 2012-2-17
8000000061 2012-2-18
8000000061 2012-2-22
8000000061 2012-2-23
8000000061 2012-2-24
8000000061 2012-2-25
8000000061 2012-2-28
8000000061 2012-2-29
8000000061 2012-3-1
8000000061 2012-3-6
8000000061 2012-3-7
8000000061 2012-3-8
8000000062 2012-2-16
8000000062 2012-2-17
8000000062 2012-2-18
8000000062 2012-2-22
8000000062 2012-2-23
8000000062 2012-2-24
8000000062 2012-2-25
8000000062 2012-2-28
8000000062 2012-2-29
8000000062 2012-3-1
8000000062 2012-3-7
8000000062 2012-3-8
8000000063 2012-2-16
8000000063 2012-2-17
8000000063 2012-2-22
8000000063 2012-2-24
8000000063 2012-2-25
8000000063 2012-2-28
8000000063 2012-2-29
8000000063 2012-3-1
8000000063 2012-3-2
8000000063 2012-3-3
8000000063 2012-3-8
8000000063 2012-3-13
8000000064 2012-2-23
8000000064 2012-2-24
8000000064 2012-2-25
8000000064 2012-2-28
8000000064 2012-3-2
8000000064 2012-3-3
8000000064 2012-3-6
8000000065 2012-2-24
8000000065 2012-2-25
8000000065 2012-2-28
8000000065 2012-3-3
8000000065 2012-3-6
8000000066 2012-3-2
8000000066 2012-3-3
8000000066 2012-3-6
8000000067 2012-3-2
8000000067 2012-3-3
8000000067 2012-3-7
8000000067 2012-3-8
8000000070 2012-3-2
8000000070 2012-3-3
8000000074 2012-2-24
8000000074 2012-2-25
8000000074 2012-2-26
8000000074 2012-3-7
8000000075 2012-2-23
8000000075 2012-2-24
8000000108 2012-3-6
8000000109 2012-2-29
8000000116 2012-3-2
8000000116 2012-3-6
8000000118 2012-2-29
8000000123 2012-3-3
8000000126 2012-3-1
8000000126 2012-3-2
8000000215 2012-4-10
8000000215 2012-4-11
8000000376 2012-4-8
8000002851 2011-11-12
8000002851 2011-12-20
8000002851 2011-12-21
8000002851 2012-2-16
8000002851 2012-2-17
8000002851 2012-2-23
8000002851 2012-2-24
8000002851 2012-3-16
8000002851 2012-3-17
8000002889 2012-2-23
8000002889 2012-2-28
8000002889 2012-3-2
8000002889 2012-3-3
8000002891 2012-2-21
8000002891 2012-2-23
8000002891 2012-2-24
8000002898 2011-11-11
8000002898 2011-11-12
8000002901 2011-11-13
8000002902 2011-11-11
8000002902 2011-11-12
8000002902 2011-12-21
8000002905 2011-11-12
8000002905 2011-11-13
8000002908 2011-12-20
8000002908 2011-12-21
8000002908 2011-12-22
8000002912 2011-11-13
8000002912 2011-11-15
8000002929 2011-12-22
8000002936 2011-12-7
8000002936 2011-12-8
8000002938 2011-12-7
8000002938 2011-12-8
8000002938 2011-12-9
8000002938 2011-12-10
8000002938 2011-12-17
8000002938 2011-12-20
8000002952 2011-12-7
8000002952 2011-12-8
8000002952 2011-12-16
8000002953 2011-12-7
8000002953 2011-12-8
8000002953 2011-12-9
8000002953 2011-12-10
8000002953 2011-12-16
8000002963 2011-12-16
8000003007 2011-12-16
8000003007 2011-12-17
8000003130 2011-12-18
8000003130 2011-12-19
8000003130 2011-12-20
8000003146 2011-12-20
8000003146 2011-12-21
8000003149 2011-12-26
8000003149 2011-12-27
8000003150 2011-12-20
8000003151 2011-12-28
8000003151 2011-12-29
8000003151 2011-12-30
8000003153 2011-12-27
8000003153 2011-12-28
8000003153 2011-12-29
8000003153 2011-12-30
8000003155 2011-12-26
8000003155 2011-12-27
8000003157 2011-12-26
8000003157 2011-12-27
8000003158 2011-12-26
8000003158 2011-12-27
8000003158 2012-1-7
8000003159 2011-12-21
8000003159 2011-12-25
8000003159 2011-12-26
8000003159 2011-12-27
8000003159 2011-12-28
8000003159 2012-1-1
8000003163 2011-12-25
8000003184 2012-1-5
8000003184 2012-1-6
8000003184 2012-1-16
8000003184 2012-1-17
8000003184 2012-1-18
8000003184 2012-2-2
8000003184 2012-2-3
8000003184 2012-2-4
8000003184 2012-2-9
8000003184 2012-2-10
8000003184 2012-2-11
8000003184 2012-2-16
8000003184 2012-2-17
8000003184 2012-2-18
8000003184 2012-2-21
8000003184 2012-2-22
8000003184 2012-2-24
8000003184 2012-2-25
8000003196 2011-12-30
8000003198 2011-12-30
8000003198 2011-12-31
8000003198 2012-1-1
8000003198 2012-1-5
8000003198 2012-1-6
8000003198 2012-1-7
8000003198 2012-1-8
8000003198 2012-1-10
8000003198 2012-1-11
8000003198 2012-1-14
8000003198 2012-1-17
8000003198 2012-1-31
8000003198 2012-2-1
8000003199 2011-12-31
8000003199 2012-1-1

Answer 1

SQL> select username from a;
 
USERNAME
----------
20120201
20120202
20120204
20120205
20120206
20120229
20120301
20120305
20120307
20120309
20120310
20120311
20120228
 
13 rows selected
 
SQL> 
SQL> select username
  2    from (select username, count(*) over(partition by ch) cnt
  3            from (select username,
  4                         to_date(username, 'yyyy-mm-dd') - row_number() over(order by username) ch
  5                    from a))
  6   where cnt >= 3
  7  ;
 
USERNAME
----------
20120204
20120205
20120206
20120228
20120229
20120301
20120309
20120310
20120311
 
9 rows selected