You can build simple expressions that limit the query results based on criteria that is applied to a single field, or you can build complex expressions that can be used to perform calculations, reformat stored values, concatenate stored values, and so on. As long as you understand the stored data and the way in which you want to present it to users, you can construct expressions to perform simple to very complex operations on the query data.
You can think of an expression as the combination of any of the following items that together define the conditions by which you want to limit the query results:
In the grid in the Conditions section, you can construct an expression in the Criteria cell, the Or cell, and the Field cell. Expressions can be constructed manually, or using the Expression Builder window, which is accessible from the Field, Criteria, and Or cells of the grid in the Conditions section.
When building expressions, you must use the base (i.e., stored) values for Units of Measure, formatted values, and translated strings. For example, consider a query that contains an expression in a field that stores numeric values in inches. To filter your query results on that field, you must specify values as they are stored in that field (i.e., in inches) rather than as they are displayed when the query is run in formatted mode (e.g., in centimeters).
For instance, to return only the records in which 25 inches has been recorded in this field, your query expression must contain the value 25, not 63.5, which is the stored value converted to centimeters, and which might be displayed to some users. To determine how you should construct values in your expressions, you can run the query in unformatted mode.