Variable (field) names must be enclosed in square brackets if they include blanks or any of the following special characters, or coincide (ignoring case) with a reserved word.

Special characters: \n (newline) \t (tab) \r (carriage return) ~ ( ) # \ / = > < + - * % & | ^ ' " [ ]

Reserved words: CHILD, PARENT, CURRENT, ORIGINAL, BEFORECHANGE, IN, LIKE, AND, OR, NOT, CONVERT, LEN, ISNULL, IIF, SUBSTRING.

Examples of escaped field name: [Order Date], [CustomerID#]

If a field name contains closing bracket, it must be escaped with \. For example, field name Customer[Name] is written as [Customer[Name\]].