An expression is a statement of intent. If you want an action to occur after meeting a specific condition, your expression must specify that condition. To select records in a query that contains ZIP field values of 90000 or higher, for example, you use the expression
You can use expressions in arithmetic calculations also. If you need an Extended Amount field in a query, for example, use
[Extended Amount]: Quantity * [Unit Price]
as the expression to create calculated values in the data cells of the Extended Amount column.
Square bracket pairs () must enclose object names, such as field names that contain spaces or punctuation other than the underscore character. You also use square ...