Calculation in Sql Server

Question

I trying to perform following calculation

Sample data:

CREATE TABLE #Table1
  (
     rno   int identity(1,1),
     ccp   varchar(50),
          


        

Answer 1

This answer may be disappointing but you'll likely find that an iterative CLR approach performs competitively with any TSQL approach.

Try the following (based on Running sums yet again: SQLCLR saves the day!)

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;

public partial class StoredProcedures
{
    [Microsoft.SqlServer.Server.SqlProcedure]
    public static void StackoverflowQuestion41803909()
    {
        using (SqlConnection conn = new SqlConnection("context connection=true;"))
        {
            SqlCommand comm = new SqlCommand();
            comm.Connection = conn;
            comm.CommandText = @"
SELECT [rno],
       [ccp],
       [col1],
       [col2],
       [col3],
       [col4]
FROM   Table1
ORDER  BY ccp,
          rno 
";

            SqlMetaData[] columns = new SqlMetaData[7];
            columns[0] = new SqlMetaData("rno", SqlDbType.Int);
            columns[1] = new SqlMetaData("ccp", SqlDbType.VarChar, 50);
            columns[2] = new SqlMetaData("col1", SqlDbType.Int);
            columns[3] = new SqlMetaData("col2", SqlDbType.Int);
            columns[4] = new SqlMetaData("col3", SqlDbType.Int);
            columns[5] = new SqlMetaData("col4", SqlDbType.Decimal, 17, 6);
            columns[6] = new SqlMetaData("result", SqlDbType.Decimal, 17, 6);

            SqlDataRecord record = new SqlDataRecord(columns);

            SqlContext.Pipe.SendResultsStart(record);

            conn.Open();

            SqlDataReader reader = comm.ExecuteReader();

            string prevCcp = null;
            decimal offset = 0;

            while (reader.Read())
            {
                string ccp = (string)reader[1];
                int col1 = (int)reader[2];
                int col3 = (int)reader[4];
                decimal col4 = (decimal)reader[5];

                if (prevCcp != ccp)
                {
                    offset = 0;
                }

                offset = ((col1 + offset) * (1 + col4));
                record.SetInt32(0, (int)reader[0]);
                record.SetString(1, ccp);
                record.SetInt32(2, col1);
                record.SetInt32(3, (int)reader[3]);
                record.SetInt32(4, col3);
                record.SetDecimal(5, col4);
                record.SetDecimal(6, col3 - offset);

                SqlContext.Pipe.SendResultsRow(record);

                prevCcp = ccp;
            }

            SqlContext.Pipe.SendResultsEnd();
        }
    }
};