Parameter Queries Using Multiple Between....And

I have created a query so that two fields have a range in them i.e.

One Field called "Price"
There are two text boxes on the seach form called "price1" and "price2"
The query reads

Between [price1] And [price2]

A second field called "Date Ordered"
There are two text boxes on the search form called "date1" and "date2"
Field called "Date Ordered"
Between [date1] And date2]

I have used the AND operator to join the first and second range. The user will fill in the criteria from a form with text boxes. This form is unbound but as soon as they click on the Search button, it will open up the query with the parameters in as above.

However, if the user were to type in a price but not a date the query shows no results. Results are only shown if a price and a date are inputted.

The OR operator will work but it is not what we need. We need to show results if a price is entered but not a date and vice versa. The fields are coming from one table.

Please can anyone advise? The database is a library management system so the price and date are the price of any books and the date that the book was ordered.

Thank you in advance for any help or advise.

Janet