Question

I am trying to delete particular tables routinely from the sys.tables in vb.net. here is code, but it does not work.

Try
    Dim MyCommand As New Odbc.OdbcCommand("", MyConnection)
    MyCommand.CommandText = "drop from sys.tables where tabname like '% " & span & "%'"
    Dim result As Integer = MyCommand.ExecuteNonQuery
    MyCommand.Dispose()
Catch ex As Exception
End Try

Answer 1

Please never try to change sysviews data. They are for your information. You change that data by executing DDL commands.

In your case you need one DROP TABLE tablename per table.
You can use sys.tables to get a list of tables to execute a DROP against, but the DROPs must be separate commands.

Also, it’s good to accustom yourself to the correct Dispose pattern:

Using MyCommand As New Odbc.OdbcCommand("drop table foo;", MyConnection)
    MyCommand.ExecuteNonQuery()  
End Using