SQL pivot function text file database with VBA Excel

Question

We do not have access to SQL server at work so I have to design an app within Excel VBA and using a text file (CSV) to store the data.

I have no problem querying data, j

Answer 1

This might not be the best of the solution, but it did work for me. I converted my data to a list and passed it to a function called "ToDataTable" to convert into datatable first.

public  DataTable ToDataTable(List items)
        {
            DataTable dataTable = new DataTable(typeof(T).Name);
            PropertyInfo[] Props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
            foreach (PropertyInfo prop in Props)
            {
                dataTable.Columns.Add(prop.Name , prop.PropertyType);
            }
            foreach (T item in items)
            {
                var values = new object[Props.Length];
                for (int i = 0; i < Props.Length; i++)
                {
                    object val;
                    val = Props[i].GetValue(item, null);
                    values[i] = val;
                }
                dataTable.Rows.Add(values);
            }
            return dataTable;
        }

Then using GetInversedDataTable() function will convert it to the format you want.

public static DataTable GetInversedDataTable(DataTable table, string columnX, 
     string columnY, string columnZ, string nullValue, bool sumValues)
{

    DataTable returnTable = new DataTable();

    if (columnX == "")
        columnX = table.Columns[0].ColumnName;

    returnTable.Columns.Add(columnY);
    List columnXValues = new List();

    foreach (DataRow dr in table.Rows)
    {

        string columnXTemp = dr[columnX].ToString();
        if (!columnXValues.Contains(columnXTemp))
        {

            returnTable.Columns.Add(columnXTemp);
        }
    }

    //Verify if Y and Z Axis columns re provided
    if (columnY != "" && columnZ != "")
    {

        List columnYValues = new List();

        foreach (DataRow dr in table.Rows)
        {
            if (!columnYValues.Contains(dr[columnY].ToString()))
                columnYValues.Add(dr[columnY].ToString());
        }

        //Loop all Column Y Distinct Value
        foreach (string columnYValue in columnYValues)
        {

            DataRow drReturn = returnTable.NewRow();
            drReturn[0] = columnYValue;
            DataRow[] rows = table.Select(columnY + "='" + columnYValue + "'");

            foreach (DataRow dr in rows)
            {
                string rowColumnTitle = dr[columnX].ToString();

                foreach (DataColumn dc in returnTable.Columns)
                {
                    if (dc.ColumnName == rowColumnTitle)
                    {

                        if (sumValues)
                        {
                            try
                            {
                                drReturn[rowColumnTitle] = 
                                     Convert.ToDecimal(drReturn[rowColumnTitle]) + 
                                     Convert.ToDecimal(dr[columnZ]);
                            }
                            catch
                            {
                                drReturn[rowColumnTitle] = dr[columnZ];
                            }
                        }
                        else
                        {
                            drReturn[rowColumnTitle] = dr[columnZ];
                        }
                    }
                }
            }
            returnTable.Rows.Add(drReturn);
        }
    }
    else
    {
        throw new Exception("The columns to perform inversion are not provided");
    }
    if (nullValue != "")
    {
        foreach (DataRow dr in returnTable.Rows)
        {
            foreach (DataColumn dc in returnTable.Columns)
            {
                if (dr[dc.ColumnName].ToString() == "")
                    dr[dc.ColumnName] = nullValue;
            }
        }
    }

    return returnTable;
}

Use it like this :

DataTable dtReturn = GetInversedDataTable(dt, "client", "emp_id", 
                                          "allocation", "0", true);

The three columns are provided and a new DataTable is returned.

The example below will use the source table and the params below to build a Pivot Table. In your case here : X axis column: "client" Y axis column: "emp_id" Z axis column: "allocation" Null value: "0"; Sum of values: true

Note that this is what I used for my problem and my code is in C#