Common Query Language (CQL)

This document describes the basic syntax of the common query language. CQL is the query language defined the Catalogue Service specification (CSW). CQL support in EOxServer is realized using the external pycql package.

This document is based upon the (E)CQL documentation of GeoServer with adapations wherever needed.

Syntax Specification

This chapter shows the syntax to define CQL queries.

Condition

condition syntax

Syntax	Description
Predicate	A single predicate expression
Condition AND | OR Condition	Logical combination of two conditions
NOT Condition	Logical inversion of a condition.
( | [ Condition ] | )	Grouping of conditions regarding evaluation order

Predicate

predicate syntax

Syntax	Description
Expression = | <> | < | <= | > | >= Expression	Comparison of two expression
Expression [ NOT ] BETWEEN Expression AND Expression	Value range Comparison
Expression [ NOT ] LIKE | ILIKE pattern	Check whether an expression matches a pattern. The % character can be used as a wildcard.
Expression [ NOT ] IN ( Expression { , Expression )	Tests the inclusion of a value in a set of values.
Expression IS [ NOT ] NULL	Tests whether the evaluated expression is NULL
Expression BEFORE Timestamp
Expression BEFORE OR DURING Period
Expression DURING Period
Expression DURING OR AFTER Period
Expression AFTER Timestamp
INTERSECTS ( Expression , Expression )
DISJOINT ( Expression , Expression )
CONTAINS ( Expression , Expression )
WITHIN ( Expression , Expression )
TOUCHES ( Expression , Expression )
CROSSES ( Expression , Expression )
OVERLAPS ( Expression , Expression )
EQUALS ( Expression , Expression )
RELATE ( Expression , Expression , pattern )
DWITHIN ( Expression , Expression , Number , units )
BEYOND ( Expression , Expression , Number , units )
BBOX ( Expression , Number , Number , Number , Number [ , CRS ] )

Expression

expression syntax

Syntax	Description
Attribute	Name of an objects attribute
Literal	A literal value
Expression + | - | * | / Expression	Arithmetic operations of two expressions
( | [ Expression ] | )	Grouping of expression regarding evaluation order

Literal

literal values

Syntax	Description
Number	A literal number (either floating point or integer
Boolean	A literal booelan value: either TRUE or FALSE
Timestamp	A timestamp literal. Must be in ISO 8601 compliant datetime format.
Duration	A timestamp literal. Must be in ISO 8601 compliant duration format.
Geometry	A Geometry in WKT format. EPSG:4326 is assumed

Period

period syntax

Syntax	Description
Timestamp / Timestamp	Period definition using the start and end timestamp.
Timestamp / Duration	Period definition using the start timestamp and a duration afterwards.
Duration / Timestamp	Period definition using the end timestamp and a duration before.

Attribute

Depending on the current query context, the following attributes are available to use in the queries.

available attributes

Attribute name	Field type	Availability
identifier	String	All
beginTime	Timestamp	All
endTime	Timestamp	All
footprint	String	All
inserted	Timestamp	All
updated	Timestamp	All
productType	String	Collection
doi	String	Collection
platform	String	Collection
platformSerialIdentifier	String	Collection
instrument	String	Collection
sensorType	String	Collection
compositeType	String	Collection
processingLevel	String	Collection
orbitType	String	Collection
spectralRange	String	Collection
wavelength	Number	Collection
parentIdentifier	String	Product
productionStatus	String	Product
acquisitionType	String	Product
orbitNumber	Number	Product
orbitDirection	Number	Product
track	Number	Product
frame	Number	Product
swathIdentifier	String	Product
productVersion	String	Product
productQualityStatus	String	Product
productQualityDegradationTag	String	Product
processorName	String	Product
processingCenter	String	Product
creationDate	Timestamp	Product
modificationDate	Timestamp	Product
processingDate	Timestamp	Product
sensorMode	String	Product
archivingCenter	String	Product
processingMode	String	Product
availabilityTime	Timestamp	Product
acquisitionStation	String	Product
acquisitionSubType	String	Product
startTimeFromAscendingNode	Number	Product
completionTimeFromAscendingNode	Number	Product
illuminationAzimuthAngle	Number	Product
illuminationZenithAngle	Number	Product
illuminationElevationAngle	Number	Product
polarisationMode	String	Product
polarizationChannels	String	Product
antennaLookDirection	String	Product
minimumIncidenceAngle	Number	Product
maximuIncidenceAngle	Number	Product
dopplerFrequency	Number	Product
incidenceAngleVariation	Number	Product
cloudCover	Number	Product
snowCover	Number	Product
lowestLocation	Number	Product
highestLocation	Number	Product