如何从一列插入多行

时间:2014-12-07 07:36:37

标签: c# sql sql-server

我想在一列中插入多行。

对于我这样的POS系统。

A

Transaction ID| Item Code|Qty|Total|Transaction Date|
-----------------------------------------------------
00001         |  Item 1  |3  |100  |12/07/2014      |
00001         |  Item 2  |2  |50   |12/07/2014      | 
00001         |  Item 3  |1  |150  |12/07/2014      |

之后我想在我的表中看到这个

Transaction ID|Item Code             |Total of Qty|Total of Price|Transaction Date|
-----------------------------------------------------------------------------------
00001         |Item 1, Item 2, Item 3|      6     |      150     | 12/07/2014     |

2 个答案:

答案 0 :(得分:1)

使用GROUP_CONCAT在GROUP BY中将字符串连接在一起:

SELECT TransactionID, GROUP_CONCAT(ItemCode) AS ItemCodes,  
       SUM(Qty) AS TotalofQty, SUM(Total) AS TotalPrice, TransactionDate
FROM TableA
GROUP BY TransactionID, TransactionDate;

SqlFiddle here

编辑将RDBMS更改为SqlServer后,需要a hack来补偿SqlServer缺少像GROUP_CONCAT这样的字符串折叠函数。这是STUFF / FOR XML PATH一个:

SELECT a.[Transaction ID], 

        STUFF((
          SELECT ',' + [Item Code]
          FROM TableA
          WHERE [Transaction ID] = a.[Transaction ID]
          FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 1, '')
     AS ItemCodes,  
       SUM(Qty) AS TotalofQty, SUM(Total) AS TotalPrice, [Transaction Date]
FROM TableA a
GROUP BY a.[Transaction ID], a.[Transaction Date];

请注意,您需要手动将STUFF subquery与相应的外部查询相关联。

SqlServer Fiddle

答案 1 :(得分:1)

确实SQL Server中没有内置的concat函数,我怀疑会有这样的。原因是创建CLR User-Defined Aggregates非常容易。实际上,MSDN上已有这样的例子。您可以在此处找到创建GROUP_CONCAT函数所需的所有内容 - String Utility Functions

基本上,您需要按照以下步骤操作:

  1. 启用CLR集成:

    sp_configure 'clr enabled', 1
    GO
    RECONFIGURE
    GO
    
  2. 创建以下C#类并构建.dll

    [Serializable]
    [Microsoft.SqlServer.Server.SqlUserDefinedAggregate(
        Microsoft.SqlServer.Server.Format.UserDefined, //use clr serialization to serialize the intermediate result
        IsInvariantToNulls = true,//optimizer property
        IsInvariantToDuplicates = false,//optimizer property
        IsInvariantToOrder = false,//optimizer property
        MaxByteSize = 8000)]    //maximum size in bytes of persisted value
    public class Concatenate : Microsoft.SqlServer.Server.IBinarySerialize
    {
        /// <summary>
        /// The variable that holds the intermediate result of the concatenation
        /// </summary>
        private StringBuilder intermediateResult;
    
        /// <summary>
        /// Initialize the internal data structures
        /// </summary>
        public void Init()
        {
            intermediateResult = new StringBuilder();
        }
    
        /// <summary>
        /// Accumulate the next value, nop if the value is null
        /// </summary>
        /// <param name="value"></param>
        public void Accumulate(SqlString value)
        {
            if (value.IsNull)
            {
                return;
            }
    
            intermediateResult.Append(value.Value).Append(',');
        }
    
        /// <summary>
        /// Merge the partially computed aggregate with this aggregate.
        /// </summary>
        /// <param name="other"></param>
        public void Merge(Concatenate other)
        {
            intermediateResult.Append(other.intermediateResult);
        }
    
        /// <summary>
        /// Called at the end of aggregation, to return the results of the aggregation
        /// </summary>
        /// <returns></returns>
        public SqlString Terminate()
        {
            string output = string.Empty;
            //delete the trailing comma, if any
            if (intermediateResult != null && intermediateResult.Length > 0)
                output = intermediateResult.ToString(0, intermediateResult.Length - 1);
            return new SqlString(output);
        }
    
        public void Read(BinaryReader r)
        {
            if (r == null) throw new ArgumentNullException("r");
            intermediateResult = new StringBuilder(r.ReadString());
        }
    
        public void Write(BinaryWriter w)
        {
            if (w == null) throw new ArgumentNullException("w");
            w.Write(intermediateResult.ToString());
        }
    }
    
  3. 部署程序集并创建函数:

    DECLARE @SamplePath nvarchar(1024)
    SET @SamplePath = 'C:\MySample\'
    
    CREATE ASSEMBLY [StringUtils] 
    FROM @SamplePath + 'StringUtils.dll'
    WITH permission_set = Safe;
    GO
    
    CREATE AGGREGATE [dbo].[Concatenate](@input nvarchar(4000))
    RETURNS nvarchar(4000)
    EXTERNAL NAME [StringUtils].[Concatenate];
    GO
    
  4. 然后您可以将此函数用作任何标准聚合函数:

    SELECT TransactionID, [dbo].Concatenate(ItemCode) AS ItemCodes,  
           SUM(Qty) AS TotalofQty, SUM(Total) AS TotalPrice, TransactionDate
    FROM TableA
    GROUP BY TransactionID, TransactionDate;
    

    注意,我已经知道CLR集成多年,但几个月前就开始使用它了。当您处理大量数据时,性能差异很大。