An AND search filter is a type of search filter that is intended to serve as a container that holds zero or more other search filters. In order for an entry to match an AND filter, it must match all of the filters contained in that AND filter.
AND filters may be represented as a string by enclosing the entire filter in parentheses and placing an ampersand just after the opening parenthesis. For example, a filter of (&(objectClass=person)(uid=john.doe)) represents an AND search filter that embeds the (objectClass=person) and (uid=john.doe) equality filters.
An AND filter that does not contain any embedded filters is called an LDAP true filter. The string representation for an LDAP true filter is an ampersand (&), and LDAP true filters will always match any target entry.