Clicking a column heading
sorts the table by that column. You can sort a table by any column,
but you can sort only by one column at a time. Clicking the column
heading works as a toggle. An upward facing arrow in the heading indicates
that the data is sorted in ascending order, and a downward facing
arrow indicates that the data is sorted in descending order. If your
table is paged (loaded as a series of pages), then sorting columns
applies only to the page of observations that you are viewing.