Simply put, the profit and loss of a position is a cumulative amount, which is the cumulative profit and loss under the same position. The profit and loss of the day is only the profit and loss of the investor on that day. If the two words are compared on the same day, the profit and loss of the position is equal to the profit and loss of the day.

In other words, as long as the stock is not completely sold, the profit and loss of the position is the cumulative sum of the profit and loss of the day. If all the stocks are sold and then bought, the profit and loss of the position should be calculated from the beginning.