Special characters can serve different functions in the query syntax.
To search for a special character that has a special function in the query syntax, you must escape the special character by adding a backslash before it, for example:
- To search for the string “where?”, escape the question mark as follows: “where\?”
- To search for the string “c:\temp,” escape the colon and backslash as follows: “c\:\\temp”
Not escaping such special characters can result in syntax errors.
| Special character | Notes on behavior when not escaped |
|---|---|
| Ampersand (&) | |
| Asterisk (*) | Used as a wildcard character. |
| At sign (@) | A syntax error is generated when an at sign is the first character of a query. In xmlxp expressions, the at sign is used to refer to an attribute. |
| Brackets [ ] | Used in xmlxp expressions to search the contents of elements and attributes. |
| Braces { } | Generates a syntax error. |
| Backslash (\) | |
| Caret (^) | Used for weighting (boosting) terms. |
| Colon (:) | Used to search in the contents of fields. |
| Equal sign (=) | Generates a syntax error. |
| Exclamation point (!) | A syntax error is returned when an exclamation point is the first character of a query. |
| Forward slash (/) | In xmlxp expressions, a forward slash is used as an element path separator. |
| Greater than symbol (>) Less than symbol (<) | Used in xmlxp expressions to compare the value of an attribute. Otherwise, these characters generate syntax errors. |
| Minus sign (-) | When a minus sign is the first character of a term, only documents that do not contain the term are returned. |
| Parentheses ( ) | Used for grouping. |
| Percent sign (%) | Specifies that a search term is optional. |
| Plus sign (+) | |
| Question mark (?) | Handled as a wildcard character. |
| Semicolon (;) | |
| Single quotation mark (‘) | Single quotation marks are used to contain xmlxp expressions. |
| Tilde (~) | Handled as proximity and fuzzy search operators. |
| Vertical bar (|) |
Escaping special characters that do not serve a special function in the query syntax is optional. The following table shows some examples of special characters that do not require escaping.
| Special character | Notes |
|---|---|
| Comma (,) | |
| Dollar sign ($) | |
| Period (.) | In xmlxp expressions, a period is used to search the content of elements. |
| Pound sign (#) | |
| Underscore (_) |