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Today, I will talk to you about how to understand CQL and ECQL in Geoserver. Many people may not understand it very well. In order to make you understand better, the editor summarized the following content for you. I hope you can get something according to this article.

CQL (Common Query Language) is a query language created by OGC and used in Catalogue Web services. Different from the query method based on xml filtering, CQL uses a format similar to text syntax and has high readability and applicability.

CQL has some limitations, such as the inability to filter id queries, and when querying, you need to specify an attribute before you can compare.

For the above reasons, GeoServer provides an extension language for CQL, called ECQL,ECQL, which removes some of the restrictions in CQL and provides a more convenient language similar to SQL.

GeoServer supports the use of CQL and ECQL in wms and wfs requests, as well as in sld (dynamic styling).

This means that when requesting Geoserver's wfs and wms services, the request can be filtered and the filtered data results can be returned.

The following is a wms request. When adding a filter request, you only need to add the corresponding parameters at the end:

Http://localhost:8080/geoserver/wms?request=GetFeatureInfo&service=WMS&version=1.1.1&layers=topp%3Astates&styles=&srs=EPSG%3A4326&format=image%2Fpng&bbox=-145.151041%2C21.73192%2C-57.154894%2C58.961059&width=780&height=330&query_layers=topp%3Astates&info_format=text%2Fhtml&feature_count=50&x=353&y=145&exceptions=application%2Fvnd.ogc.se_xml

/ / filter the concatenated strings

& cql_filter=INTERSECTS (the_geom,%20POINT%20 (- 74.817265% 2040.5296504))

The following is a wfs request, which filters the fields based on the parameters. You only need to add the corresponding parameters later:

Http://example.com/geoserver/wfs? Service=wfs& version=2.0.0& request=GetFeature& typeNames=namespace:featuretype

Cql_filter=INTERSECTS (the_geom,%20POINT%20 (- 74.817265% 2040.5296504))

According to the above filtering, you can control the data information displayed on the map, or the query information, which needs to be requested according to the service.

After reading the above, do you have any further understanding of how to understand CQL and ECQL in Geoserver? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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