histogramQueries property

An expression specifying a histogram request against matching documents.

Expression syntax is an aggregation function call with histogram facets and other options. The following aggregation functions are supported: * count(string_histogram_facet): Count the number of matching entities for each distinct attribute value. Data types: * Histogram facet (aka filterable properties): Facet names with format <schema id>.<facet>. Facets will have the format of: a-zA-Z. If the facet is a child facet, then the parent hierarchy needs to be specified separated by dots in the prefix after the schema id. Thus, the format for a multi- level facet is: <schema id>.<parent facet name>. <child facet name>. Example: schema123.root_parent_facet.middle_facet.child_facet * DocumentSchemaId: (with no schema id prefix) to get histograms for each document type (returns the schema id path, e.g. projects/12345/locations/us-west/documentSchemas/abc123). Example expression: * Document type counts: count('DocumentSchemaId') * For schema id, abc123, get the counts for MORTGAGE_TYPE: count('abc123.MORTGAGE_TYPE')