Final answer:
A crosstab query is used when you want to describe one field in terms of two or more fields in a table.
Step-by-step explanation:
A Crosstab query is used when you want to describe one field in terms of two or more fields in the table. It allows you to summarize data in a table by showing the intersections between two or more fields. For example, you can use a crosstab query to display the total sales for each product category and month.