The criteria element must be a valid JSON format statement composed of the criteria that specify the items that should be returned. It is essentially a compound boolean statement, and only elements for which the statement evaluates to true are returned by the query.
Each criterion is essentially a comparison statement that is applied either to a field or a property. Please see the full list of Comparison Operators. While each criterion may be expressed in complete general format, AQL defines shortened forms for readability as described below.