I have a following SQL statement and would like to update Database table if row found.

```
string sql = "Select A.CNum FROM TABLEA A, TABLEB B WHERE A.CID= B.CID AND A.CNum is NULL AND CID=@cID"

DataTable dt = querySql(sql, params);

                if (dt.Rows.Count > 0)
                {
                    // I would like to update CNum from TableA
                }

```

What is the best method to update the row from SQL Statement?

Thank you..