Generally, you should enclose strings in double quotation marks. Examples of strings are "c35product2" and "referrerID".

To indicate special characters in a string, use a backslash (for example, "\$65443"). (To indicate a backslash character, use a double backslash, \\.) You can use single quotes around a string, but the result is indistinguishable from a quoted field ('referrerID'). See String functions for more information.