Filtering data with CQL
Another vendor parameter is
cql_filter. It allows users to add filters to requests using Extended Common Query Language (ECQL).
In the previous recipes, you created filters using the OGC filter XML standard. ECQL lets you create filters in an easier text format and in a much more compact way. A CQL filter is a list of phrases similar to the
where clauses in SQL, each separated by the combiner words AND or OR.
CQL was originally used for catalog systems. GeoServer uses an extension for CQL, allowing the full representation of OGC filters in the text form. This extension is called ECQL.
ECQL lets you use several operators and functions. For more information, you can read the documents available at the following URLs: