title: DATEDIFF with variable seed
body: <p>I have the following table</p>
  
  <p><img src="https://i.stack.imgur.com/T9tPV.png" alt="enter image description here"></p>
  
  <p>The first column are transaction dates order by Date DESC. 
  The second column is binary state for each transaction, could be either 0 or 1. 
  The third column is the datediff of the minimum date compared to each date. 
  the code that produces this table is something like that  </p>
  
  <pre><code>DECLARE @date DATE 
  SELECT @Date = MIN(CONVERT(DATE,Transaction_Created)) FROM #dates
  SELECT      CONVERT(DATE,Transaction_Created)                       AS Date
      ,       MAX(Is_Deposit)                                         AS Is_Deposit
      ,       DATEDIFF(dd,@Date,CONVERT(DATE,Transaction_Created))    AS Datedif  
  
  FROM        #DATES
  GROUP BY    CONVERT(DATE,Transaction_Created)
  order by 1 desc
  </code></pre>
  
  <p>My problem is that when is_Deposit=1 i need to reset my seed for DATEDIFF and the date of IS_Deposit =1 become my new MIN Date and so on for each IS_Deposit=1 i find in the table.
  For example from 2015-12-04 until 2015-12-16 everything is ok. But in line 746 2015-12-17 i would like this to be 1 again and not 13 as we have reached the next IS_Deposit=1 and we have to reset. </p>
  
  <p>Resultset now:</p>
  
  <pre><code>Date    Is_Deposit  Datedif
  
  2016-02-12  0   70
  2016-02-11  0   69
  2016-02-10  0   68
  2016-02-09  0   67
  2016-02-08  0   66
  2016-02-07  0   65
  2016-02-06  0   64
  2016-02-05  0   63
  2016-02-04  0   62
  2016-02-03  0   61
  2016-02-02  0   60
  2016-02-01  0   59
  2016-01-31  0   58
  2016-01-30  0   57
  2016-01-29  0   56
  2016-01-28  0   55
  2016-01-27  0   54
  2016-01-26  0   53
  2016-01-25  0   52
  2016-01-24  0   51
  2016-01-23  0   50
  2016-01-22  0   49
  2016-01-21  0   48
  2016-01-20  1   47
  2016-01-17  0   44
  2016-01-16  0   43
  2016-01-15  0   42
  2016-01-14  0   41
  2016-01-13  0   40
  2016-01-12  0   39
  2016-01-11  0   38
  2016-01-10  0   37
  2016-01-09  0   36
  2016-01-08  0   35
  2016-01-07  0   34
  2016-01-06  0   33
  2016-01-05  0   32
  2016-01-04  0   31
  2016-01-03  0   30
  2016-01-02  0   29
  2016-01-01  0   28
  2015-12-31  0   27
  2015-12-30  0   26
  2015-12-29  0   25
  2015-12-28  0   24
  2015-12-27  0   23
  2015-12-26  0   22
  2015-12-25  1   21
  2015-12-20  0   16
  2015-12-19  0   15
  2015-12-18  0   14
  2015-12-17  0   13
  2015-12-16  1   12
  2015-12-14  0   10
  2015-12-13  0   9
  2015-12-12  0   8
  2015-12-11  0   7
  2015-12-10  0   6
  2015-12-09  0   5
  2015-12-08  0   4
  2015-12-07  0   3
  2015-12-05  0   1
  2015-12-04  1   0
  </code></pre>
  
  <p>Resultset Required:</p>
  
  <pre><code>2016-02-12  0   23
  
  2016-02-11  0   22
  2016-02-10  0   21
  2016-02-09  0   20
  2016-02-08  0   19
  2016-02-07  0   18
  2016-02-06  0   17
  2016-02-05  0   16
  2016-02-04  0   15
  2016-02-03  0   14
  2016-02-02  0   13
  2016-02-01  0   12
  2016-01-31  0   11
  2016-01-30  0   10
  2016-01-29  0   9
  2016-01-28  0   8
  2016-01-27  0   7
  2016-01-26  0   6
  2016-01-25  0   5
  2016-01-24  0   4
  2016-01-23  0   3
  2016-01-22  0   2
  2016-01-21  0   1
  2016-01-20  1   26
  2016-01-17  0   23
  2016-01-16  0   22
  2016-01-15  0   21
  2016-01-14  0   20
  2016-01-13  0   19
  2016-01-12  0   18
  2016-01-11  0   17
  2016-01-10  0   16
  2016-01-09  0   15
  2016-01-08  0   14
  2016-01-07  0   13
  2016-01-06  0   12
  2016-01-05  0   11
  2016-01-04  0   10
  2016-01-03  0   9
  2016-01-02  0   8
  2016-01-01  0   7
  2015-12-31  0   6
  2015-12-30  0   5
  2015-12-29  0   4
  2015-12-28  0   3
  2015-12-27  0   2
  2015-12-26  0   1
  2015-12-25  1   9
  2015-12-20  0   4
  2015-12-19  0   3
  2015-12-18  0   2
  2015-12-17  0   1
  2015-12-16  1   12
  2015-12-14  0   10
  2015-12-13  0   9
  2015-12-12  0   8
  2015-12-11  0   7
  2015-12-10  0   6
  2015-12-09  0   5
  2015-12-08  0   4
  2015-12-07  0   3
  2015-12-05  0   1
  2015-12-04  1   0
  </code></pre>