Ambiguous column name 'btopicId'.

Question

string MyQuery = "SELECT tblBlogTopic.btopicId, tblBlogTopic.btopicTitle, tblBlogTopic.btopicDescription, tblBlogComment.bCommentDescriptin, tblBlogComment.bcdatetime, tblBlogComment.Empid FROM tblBlogTopic INNER JOIN tblBlogComment ON tblBlogTopic.btopicId = tblBlogComment.btopicId where (btopicId='" + lstboxforblogtitle.SelectedValue + "')";

While running the above query, i am getting the following error.
" Ambiguous column name 'btopicId' "

Could anyone plz help me.