fill a dataset with several requests

[Sam]

Hi,
I'm trying to fill a dataset using two requests :

select column_name as column_name1, data_type as data_type1
from information_sch ema.columns
where table_name = 'table1'

and

select column_name as column_name2, data_type as data_type2
from information_sch ema.columns
where table_name = 'table2'

after the first request I fill my dataset like this :

myCommand = New SqlCommand(sql. ToString, con)
da.SelectComman d = myCommand
da.Fill(dsField s)

I don't know how to add two columns to my dataset and fill them with
the two fields selected by my second request.
The reason I want to do this is, I want to fill the first two columns
of a datagrid with the first two of the dataset using parameter
'table1', and to fill the last two columns of the datagrid with the
last two of the dataset filled with the second request (parameter
'table2)

It's quite tricky I find.
Can someone help ?
thx