How to compare values of two datatable columns

Question

I want to validate quantity columns of two datatable. Given below is the sample datatable. I want to take the sum of the quantity of each item from dtItems and compare with the quantity of same item in dtMasterItem . If dtItems quantity become greater than dtMasterItem quantity then I want show the message like Available quantity is 1000 for itemcode

dtMasterItem

ItemCode      Quantity

  A            3000    
  B            5000    
  C            6000 

dtItems

ItemCode      Quantity

   A           2000
   A           1000
   A           500
   B           3000  
   B           2000  
   C           6000 

As per my logic if we validate the above table data the output will be like Available quantity is 3000 for A

Answer 1

Your question isn't that clear but according to what I understood from it this ought to do it for you.

        foreach (DataRow rowMasterItems in dtMasterItem.Rows)
        {
            int lintSumOfItems = 0;
            foreach (DataRow rowItems in dtItems.Rows)
            {
                if (rowMasterItems["ItemCode"].ToString().Equals(rowItems["ItemCode"].ToString()))
                {
                    lintSumOfItems += Convert.ToInt16(rowItems["Quantity"]);
                }
            }
            if (Convert.ToInt16(rowMasterItems["Quantity"]) >= lintSumOfItems)
                MessageBox.Show("OK");
            else
                MessageBox.Show("Available quantity is " + Convert.ToInt16(rowMasterItems["Quantity"]) + " for itemcode: " + rowMasterItems["ItemCode"].ToString());
        }

Answer 2

Try this code, it worked for me:

        DataTable dt1 = new DataTable();
        DataTable dt2 = new DataTable();
        dt1.Columns.Add("ItemCode", typeof(string));
        dt1.Columns.Add("Quantity", typeof(int));
        dt2.Columns.Add("ItemCode", typeof(string));
        dt2.Columns.Add("Quantity", typeof(int));
        dt1.Rows.Add("A", 3000);
        dt1.Rows.Add("B", 5000);
        dt1.Rows.Add("C", 6000);
        dt2.Rows.Add("A", 2000);
        dt2.Rows.Add("A", 1000);
        dt2.Rows.Add("A", 500);
        dt2.Rows.Add("B", 3000);
        dt2.Rows.Add("B", 2000);
        dt2.Rows.Add("c", 6000);

        var query = from row in dt2.AsEnumerable()
                    group row by row.Field<string>("ItemCode") into grp
                    select new
                    {
                        ItemCode = grp.Key,
                        Quantity = grp.Sum(r => r.Field<int>("Quantity"))
                    };
        int i = 0;
        foreach (var item in query)
        {
            if (Convert.ToInt32(item.Quantity) > Convert.ToInt32(dt1.Rows[i]["Quantity"]))
            {
                Console.WriteLine("Available quantity is "+ dt1.Rows[i]["Quantity"].ToString()+ " for "+item.ItemCode);
            }
            i++;
        }

        Console.Read();

Answer 3

Try this using linq query

    DataTable dt1 = new DataTable("dtMasterItem");
    dt1.Columns.Add(new DataColumn() { DataType = typeof(string), ColumnName = "ItemCode" });
    dt1.Columns.Add(new DataColumn() { DataType = typeof(int), ColumnName = "Quantity" });

    DataTable dt2 = new DataTable("dtItems");
    dt2.Columns.Add(new DataColumn() { DataType = typeof(string), ColumnName = "ItemCode" });
    dt2.Columns.Add(new DataColumn() { DataType = typeof(int), ColumnName = "Quantity" });

    dt1.Rows.Add("A", 3000);
    dt1.Rows.Add("B", 5000);
    dt1.Rows.Add("C", 6000);

    dt2.Rows.Add("A", 2000);
    dt2.Rows.Add("A", 1000);
    dt2.Rows.Add("A", 500);
    dt2.Rows.Add("B", 3000);
    dt2.Rows.Add("B", 2000);
    dt2.Rows.Add("C", 6000);

   var result = (from k in
                  (from x in dt2.AsEnumerable()
                           group x by x["ItemCode"] into entryGroup
                           select new
                           {
                               ItemCode = entryGroup.Key,
                               Quantity = entryGroup.Sum(i => Convert.ToInt32(i["Quantity"]))
                           })
                      join y in dt1.AsEnumerable() on k.ItemCode equals y["ItemCode"] into DataGroup
                      from item in DataGroup.DefaultIfEmpty()
                      select new
                      {
                          ItemCode = k.ItemCode,
                          Q1 = k.Quantity,
                          Q2 = item["Quantity"],
                          Remarks = Convert.ToInt32(item["Quantity"]) < k.Quantity ? "Available quantity is " + k.Quantity + " for " + k.ItemCode : null
                      }).AsEnumerable().Where(i => i.Remarks != null);

Output :