Return top 5 records of a table in a dataset.

Question

I want to return the top 5 records of a table in a dataset for datagrid view. The following does not work.

DataGridView.DataSource = DS.Tables("TABLENAME").Select("SELECT TOP 5")

Any suggestions?

Using Visual Studio 2008 - VB.Net

Answer 1

How about using the TOP clause. THis assume you are using SQL Server.

ie Select top 5 * from SomeTable

If you are using MySQL there is the limit clause

If you are using Oracle lookup ROWNUM

Answer 2

Select doesn't work like that, take a look at the syntax.

What you want to do is create a View with your table, sort it and take the first five rows.

DataView view = DS.Tables[0];
view.Sort = "myColumn";
//Take first or last 5 rows.

Or of course just use a "SELECT TOP 5 x from mytable" and insert that into your datatable.

Answer 3

If you're using SQL Server 2005 or greater, you could use the ROW_NUMBER() function to number the rows, then use:

DS.Tables("TABLENAME").Select("row_number <= 5")

Answer 4

If the dataset is already populated, you can use LINQ to take the first 5 rows from a table. (The more efficient method would be to handle this at the database, however.)

Dim rows = DS.Tables("Foo").Rows.Cast(Of DataRow)().Take(5)