如何在列中分组行值并将行转换为列？

Question

我的需求如下：在sql 2005中使用sql查询，如果可能的话要避免存储过程。

EmpType EmpName   Role 

1    Ram  Admin 

2    Raja  Admin 

1    John  update 

2    Tom  Admin 

1    Adam  Admin 

我需要的empType A组输出是这样的：

EmpType  EmpName   Admin  Update 

1    Ram, John, Adam Adam,Ram John 

2    Raja , Tom  Tom,Raja 

谁能帮我。

感谢，

Answer 1

要执行你需要编写concatinates字符串自己的聚合功能的任务。这里有一个例子：

using System; 
using System.Collections.Generic; 
using System.Data.SqlTypes; 
using System.IO; 
using Microsoft.SqlServer.Server; 

[Serializable] 
[SqlUserDefinedAggregate(Format.UserDefined, MaxByteSize=8000)] 
public struct strconcat : IBinarySerialize{ 
     private List values; 

     public void Init() { 
      this.values = new List(); 
     } 

     public void Accumulate(SqlString value) { 
      this.values.Add(value.Value); 
     } 

     public void Merge(strconcat value) { 
      this.values.AddRange(value.values.ToArray()); 
     } 

     public SqlString Terminate() { 
      return new SqlString(string.Join(", ", this.values.ToArray())); 
     } 

     public void Read(BinaryReader r) { 
      int itemCount = r.ReadInt32(); 
      this.values = new List(itemCount); 
      for (int i = 0; i <= itemCount - 1; i++) { 
       this.values.Add(r.ReadString()); 
      } 
     } 



     public void Write(BinaryWriter w) { 
      w.Write(this.values.Count); 
      foreach (string s in this.values)  { 
       w.Write(s); 
      } 
     } 
} 

查询将是：

SELECT * FROM 
(Select EmpType, EmpName, Role 
FROM TableName) t 
PIVOT 
(
    dbo.strconcat(EmpName) FOR Role IN ([Admin], [update]) 
) p 

您可能还需要检查this link

Answer 2

如果你不想创建额外的结构（存储过程，函数等等）这就是你要找的东西：

select 
    EmpType, 
    stuff((select ', ' + EmpName from tmp t2 where t2.EmpType = t1.EmpType 
      for xml path('')),1,2,'') EmpName, 
    stuff((select ', ' + EmpName from tmp t2 where t2.EmpType = t1.EmpType and t2.Role = 'Admin' 
      for xml path('')),1,2,'') [Admin], 
    stuff((select ', ' + EmpName from tmp t2 where t2.EmpType = t1.EmpType and t2.Role = 'Update' 
      for xml path('')),1,2,'') [Update] 
from tmp t1 
group by EmpType