根据SQL存储过程(或LINQ)透视

这对我很有用,应该在SP中工作:

SELECT  theID AS ID
       ,[2] AS CHOICE
       ,[3] AS COUNT
       ,[4] AS SORT
FROM    so_666934 PIVOT ( MAX(theValue) FOR theGroup IN ([2], [3], [4]) ) AS pvt

您可以使用动态SQL来处理随时间变化的组,还可以通过有效地将组替换为透视前的名称来透视名称。

下面是用Linq在内存中实现这一点的几种方法。

List<SomeClass> source = new List<SomeClass>()
{
  new SomeClass(){ theID = 1, theGroup = 2, theValue="Red"},
  new SomeClass(){ theID = 2, theGroup = 2, theValue="Blue"},
  new SomeClass(){ theID = 3, theGroup = 2, theValue="Green"},
  new SomeClass(){ theID = 1, theGroup = 3, theValue=10},
  new SomeClass(){ theID = 2, theGroup = 3, theValue=24},
  new SomeClass(){ theID = 3, theGroup = 3, theValue=30},
  new SomeClass(){ theID = 1, theGroup = 4, theValue=1},
  new SomeClass(){ theID = 2, theGroup = 4, theValue=2},
  new SomeClass(){ theID = 3, theGroup = 4, theValue=3}
};

//hierarchical structure
var result1 = source.GroupBy(item => item.theID)
  .Select(g => new {
    theID = g.Key,
    theValues = g
      .OrderBy(item => item.theGroup)
      .Select(item => item.theValue)
      .ToList()
  }).ToList();


//holds some names for the next step.
Dictionary<int, string> attributeNames = new Dictionary<int,string>();
attributeNames.Add(2, "CHOICE");
attributeNames.Add(3, "COUNT");
attributeNames.Add(4, "SORT");
//xml structure
var result2 = source
  .GroupBy(item => item.theID)
  .Select(g => new XElement("Row",
    new XAttribute("ID", g.Key),
    g.Select(item => new XAttribute(attributeNames[item.theGroup], item.theValue))
  ));