how to show data using two table in c# .net

Question

how display data using two table i am use one text box and one button and one datagrideview and two table i am use following query SqlDataAdapyer asdf= new sqldataadapter("select * from sem1,sem2 wher cid=''"+textbox1.text+"",con); datatable dt = new datatable; dt.Fill(dt); Gridviewer.datasource=dt; but data show only sem1 in datagrideview.