Question

I have two DataTables. I want to get what exists in the first one but does not exist in the second one. I would like the results in another DataTable. I would like to use LINQ.

• The First datatable:

---

DataTable dt1 = cc1roleDAL.GetAll(x, 0);

• The second datatable:

---

DataTable dt2 = cc1roleDAL.GetSpecific(x);

Note: the column names I return from the the two datatables:

1. crs_name

2. name

Answer 1

This will do the trick for you:

var rowsOnlyInDt1 = dt1.AsEnumerable().Where(r => !dt2.AsEnumerable()
                    //make sure there aren't any matching names in dt2
                    .Any(r2 => r["crs_name"].Trim().ToLower() == r2["crs_name"].Trim().ToLower() && r["name"].Trim().ToLower() == r2["name"].Trim().ToLower()));

or if you prefer query syntax:

var rowsOnlyInDt1 = from r in dt1.AsEnumerable()
                    //make sure there aren't any matching names in dt2
                    where !dt2.AsEnumerable().Any(r2 => r["crs_name"].Trim().ToLower() == r2["crs_name"].Trim().ToLower() && r["name"].Trim().ToLower() == r2["name"].Trim().ToLower())
                    select r;

You can then put the results into a DataTable by using the CopyToDataTable function:

DataTable result = rowsOnlyInDt1.CopyToDataTable();