Table View - adding a column with sql SELECT output value

Hi,
I've got a Table View with some CCK fields in it. I want to add a new column with some sql SELECT output value. My node type is in parent-child relation with other node type and I want to print in this column a number of 'children' for each parent (row). It can be done by something like that: 'select count(*) from table where table.nid = cNID' where cNID is a row NID (node id in a current row, for each row in Table View). Anyway, I just want to add a column to a Table View with some Select output value for each row. How can I do that ? Thank you for any suggestions.