DataTable.Compute Issue

Question

 

Hello All,

first off I'm using Visual Studio 2010, framework 4.0

What am I trying to achieve:
well, I'm getting info from my SQL database and put it into a DataTable,  I then need to do a calculation PER ROW so I add another column to my datatable (ColumnV - datatype = decimal)

here is a sample of what my data looks like: Last Column = ColumnV

1234	31224	ROWA	6020941N9999	VLIES	24875.17	1122011	800	40753	40759	40759	139	PKGS	3536	FCL	40370017	60282960	MRKU 223 190-7	40FT	0
1246	3…	ROWA	6045999N	FLEECE		1122011	5	40753	40759	40759				FCL	40370017	60282960	MRKU 223 190-7	40FT	0
1248	3…	KOSTAL IRELAND	0277241AA	SEAT MEMORY	12284.22	1122011	624	40750	40752	40760	1	PAL	167	1.123	80440792	90032500	MSKU 041089-1	40FT	0
1249	3…	KOSTAL IRELAND	0277242AA	SEAT MEMORY		1122011	390	40750	40752	40760					80440794	90032500	MSKU 041089-1	40FT	0
1250	3…	JOHNSON LAHNWERK	6027134L	ZB STRUKTUR	9377.94	1122011	432	40752	40756	40760	24	PAL	4464	28.759	21036789	1260135088	MSKU 041089-1	40FT	14.364
1251	3…	JOHNSON LAHNWERK	6027126R	ZB STRUKTUR		1122011	432	40752	40756	40760					21036789	1260135088	MSKU 041089-1	40FT	14.364

 

All good and well but now for my next challenge - I need to add another column to my datatable - and ONLY write to it once the value of the container change (3rd last column with values e.g. MSKU 041089-1)

with the below code i tried to achieve this - but NO luck

Could you please spare me some of your time and help me out with my issue:

        public System.Data.DataTable Calc(System.Data.DataTable ACTable)
        {
            string i_sGroupByColumn = "CONTAINER";

            //adding column for the row count 
            ACTable.Columns.Add("Results", typeof(decimal));

            //looping thru distinct values for the group, counting 
            foreach (DataRow dr in ACTable.Rows)
            {
                for (int i = 0; i < ACTable.Rows.Count; i++)
                {
                    System.Data.DataTable dtContainer = new System.Data.DataTable();
                    dtContainer = GetData.GetContainerSize(ACTable.Rows[i]["Type"].ToString());
                    decimal dContainerSize = Convert.ToDecimal(dtContainer.Rows[0]["Container_Size"].ToString());

                    string cExpr = "SUM(CONVERT(ColumnV, 'System.Decimal'))";
                    string cCond = i_sGroupByColumn + " = '" + dr[i_sGroupByColumn] + "'";

                    decimal dSumVal = (decimal)(ACTable.Compute(cExpr, cCond));
                    dr["Results"] = dSumVal / dContainerSize;
                }  
            } 
            return ACTable;
        }

currently its bombing out on: decimal dSumVal = (decimal)(ACTable.Compute(cExpr, cCond));
with error:

Syntax error in aggregate argument: Expecting a single column argument with possible 'Child' qualifier.

Please please please  - i need to have this project done by 5th December :(