如何在SQL中对此进行分组

Question

我有这个选择

Trip Sequence Shipment Place
=================================
102  10       4798     Amsterdam
102  20       4823     Utrecht
102  30       4831     Utrecht
102  40       4830     Rotterdam
102  50       4790     Rotterdam
102  60       4840     Utrecht
102  70       4810     Amsterdam

我希望这样分组：

 Trip  Group Place
 ==========================
  102  1     Amsterdam
  102  2     Utrecht
  102  3     Rotterdam
  102  4     Utrecht
  102  5     Amsterdam

如何在SQL Server中实现此目的？ @Giorgos Betos的答案很棒。后续问题：如何将这些groupnumbers分配给原始表的行？

Answer 1

试试这个：

SELECT Trip, Place, 
       ROW_NUMBER() OVER (ORDER BY MinSequence) AS [Group]
FROM (
  SELECT Trip, Place, MIN(Sequence) AS MinSequence
  FROM (
    SELECT Trip, Place, Sequence,
           ROW_NUMBER() OVER (ORDER BY Sequence) - 
           ROW_NUMBER() OVER (PARTITION BY Trip, Place 
                              ORDER BY Sequence) AS grp
    FROM mytable) AS x
  GROUP BY Trip, Place, grp) AS t

Demo here

修改

要获取原始未分组表格中的排名数字，您可以使用DENSE_RANK：

SELECT Trip, Place, Sequence,
       DENSE_RANK() OVER (ORDER BY grp) AS [Group]
FROM (       
  SELECT Trip, Place, Sequence,
         MIN(Sequence) OVER (PARTITION BY Trip, Place, grp) AS grp
  FROM (                          
    SELECT Trip, Place, Sequence,
           ROW_NUMBER() OVER (ORDER BY Sequence) - 
           ROW_NUMBER() OVER (PARTITION BY Trip, Place 
                              ORDER BY Sequence) AS grp
    FROM mytable) AS t) AS x
ORDER BY Sequence 

Demo here