Avoid duplicates in linq based on single column - asp.net

Question

i have been retrieving data from datatable using linq.i have retrieved the data successully too.the problem is ,i have to show only one record if two records have same projectname (irrespective of which record,but one record must be shown from the dupicate records).
for multiple records with same projectname, only one record from it should be shown.
I have pasted my working code.
cmd.CommandText = " Select PROJECTNAME,COMPANY,PROJECTSTATUS,STARTEDIN,COMPLETEDIN FROM CMPPROJECT WHERE STATUS ='" + a + "'";
using (OracleDataAdapter sda = new OracleDataAdapter())
{
cmd.Connection = con;
sda.SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
dt.TableName = "CMPPROJECT";
sda.Fill(dt);
var select = (from ab in dt.AsEnumerable()
select new { c1 = ab["PROJECTNAME"], c2 = ab["COMPANY"], c3 = ab["PROJECTSTATUS"], c4 = ab["STARTEDIN"], c5 = ab["COMPLETEDIN"] }).Distinct().ToList();
dt.Clear();
foreach (var item in select)
dt.Rows.Add(item.c1, item.c2, item.c3, item.c4, item.c4);
return dt;
}
Please help me with modified working code..

Answer 1

You can use GroupBy:
var projectGroups = dt.AsEnumerable()
.Select(row => new
{
project = row.Field<string>("PROJECTNAME"),
company = row.Field<string>("COMPANY"),
status = row.Field<string>("PROJECTSTATUS"),
startedin = row.Field<DateTime>("STARTEDIN"), // presumes a DateTime-column
completedin = row.Field<DateTime>("COMPLETEDIN") // presumes a DateTime-column
})
.GroupBy(x => x.project)
.Select(g => g.First())
.Distinct()
.ToList();