extract data from a dataset

Question

I have a dataset that gets populated from a stored proc in sql server. I have a column that has lets say has a set of values. I do not know what those values are. All I know is that they of the type "string". I want to extract all the distinct values from that column.

Answer 1

You can simply use Select method of the DataTable :

DataRow[] extractedRows = 
     yourDataSet.Tables["YourTableName"].Select("YourColumnName = 123");

Answer 2

You can also use Linq to query your datatables. Here is a link to some examples on the MS site - http://msdn.microsoft.com/en-us/vbasic/bb688086.aspx

Answer 3

You can use a DataView and set its RowFilter to the desired condition:

var view = new DataView(dataset.Tables["Table"]);
view.RowFilter = "Column = 42";

UPDATE: based on your updated question, you can use LINQ:

var table = dataset.Tables["Table"].AsEnumerable();
var distinctValuesForColumn = 
  table.Select(row => (string)row["Column"]).Distinct();

Answer 4

I hope below statement will serve your purpose

ds.Tables["TableName"].DefaultView.ToTable( true, "columnName"); //For Dataset (true means distinct)

OR

   `ds.Tables[0].DefaultView.ToTable( true, "columnName");

//For Dataset where tableindex is 0

OR

dt.DefaultView.ToTable( true, "columnName"); //For Datatable

//Syntax is like Datatable.DefaultView.ToTable( Distinct true/false, “ColumnName”);

MSDN : http://msdn.microsoft.com/en-us/library/wec2b2e6.aspx