The query string (or match pattern) can include regular characters and wildcard characters. Regular characters must match exactly the characters specified in the query string. Wildcard characters can be matched with arbitrary fragments of the query string. Wildcard characters can be escaped using the single backslash () character. Use a double backslash (\) to match a single backslash. The syntax of the query string has the following rules:
- If null or empty string, then everything will be matched.
- If no wildcards, then an exact match on the query string is performed.
- Wildcard * can be placed anywhere in the query string and matches zero or more characters.
- Wildcard ? can be placed anywhere in the query string and matches exactly one character.
- One character in a set of characters are matched by placing them within [ ] . For example, a[bc] would match 'ab' or 'ac', but it would not match 'ad' or 'abd'.
- One character in a set of characters are not matched by placing them within [! ] . For example, a[!bc] would match 'ad', but it would not match 'ab', 'ac', or 'abd'.