SOLR Aggregate Queries

1 Group Queries Overview:There are two types of group queries commonly used in SOLR, facet groupings and group groupings, with the following two queries:
1.1 facet Groupings

The query results of the SOLR species for navigation are faceted, and the count information is added according to the classification on the results of the user query, and then the user makes a further search based on the count information.

Facet is one of SOLR's advanced search features that gives users a more user-friendly search experience. While searching for keywords, you can group and count the fields of the facet.

SOLR Fact provides 4 types of fact

<lstname= "Facet_counts" > 
  <lstname= "facet_queries"/> <lstname= 
  "Facet_fields"/> 
  <lstname= "Facet_dates"/> 
  <lstname= "facet_ranges"/> 
</lst> 
facet_queries: Represents a custom conditional query facet, a database-like count function
Facet_fields    : Represents a grouping of queries based on fields, a combination of groupby count that resembles a database
facet_ Dates: Group query according to date interval
facet_ranges: Of course, the date has the interval, the number also has, this is according to the number grouping query

Description

The basic function of facets is to classify the data in the search results.

Facet Usage

Facet.field: Specifies the field to classify
Facet=on or facet=true indicates that the function is turned
on facet.prefix indicates the field prefix
facet.limit indicates the number
of records returned Facet.offict means starting from the first, mainly for paging
facet.query can arbitrarily define the query
  

Range Facet

Fields that are typically used for date types or numeric types.

&facet=on
&facet.query=date:[2009-1-1t0:0:0zto 2010-1-1t0:0:0z]

Parameter description

Facet.range   need to do facet query field
facet.range.start      set start point
facet.range.end       set end point
Facet.range.gap       limits the interval difference for each range
facet.range.hardend          specifies how to handle the last interval
facet.range.include Specify how the threshold is handled
facet.range.other    Specifies how to handle the result of a bounded range
facet.range.method           Specify the facet algorithm

The following query:

http://localhost:8983/solr/solr_select/query?q=*:* &facet=on&facet.field=name

Group query results by Name field

1.2 Group Group

SOLR Group processing of results can also be used in addition to facets. The SOLR group is a field that groups the results, returning the results in each group that satisfy the query sequentially.

Group contrast facet

The concept of group and facet is very similar, it is used to group. Facets return all relevant results and allow the user to redefine the result set based on the facet's catalog. Facets can filter the number of groups, as well as sorting, and date range, time range groupings, but if you want to get specific data, you need to query one or more times. Group can get the number of groups grouped, one request, can get all the data.

Group and facet can be used together, but only Facet.field and Facet.range are used, and date and dimension statistics pivot faceting are not supported.

The following query:

http://localhost:8983/solr/solr_select/query?q=*:* &group=true&group.field=name

Parameter description:

Parameters	type	Description
Group	Boolean value	Set to true to indicate that the result needs to be grouped
Group.field	String	Fields that need to be grouped, Strfield or TextField when the field type is required
Group.func	Query statements	You can specify a query function
Group.query	Query statements	You can specify a query statement
Rows	Integer	Returns how many groups of results, default 10
Start	Integer	Specify the result start position/offset
Group.limit	Integer	Returns multiple results per group, default 1
Group.offset	Integer	Specify the start position/offset of each set of results
Sort	Sorting algorithms	Control the return order of individual groups
Group.sort	Sorting algorithms	Control the order within each grouping
Group.format	Grouped/simple	Set to simple to allow results to be returned as a single list
Group.main	Boolean value	When set to true, the result will be determined primarily by the grouping command for the first field
Group.ngroups	Boolean value	When set to True, SOLR returns the number of packets, the default Fasle
Group.truncate	Boolean value	When set to true, the number of facets will be based on the document with high correlation in group grouping, default Fasle
Group.cache.percent	Integer 0-100	is set to greater than 0 o'clock, which indicates the cached result, which defaults to 0. The key for Boolean query, wildcard query, fuzzy query has improved, but will slow down the common word query.

2 Stats Component aggregation query

Summary: SOLR can use statscomponent to implement aggregated statistical queries on numbers, strings, or date fields, that is:min, max, AVG, COUNT, sum functions

Stats Component Parameter Description:

Parameters	Description
Stats	Boolean value, set to True to open stats Component
Stats.field	Specify the fields that need to be counted
Stats.facet	Generates a child result set for the specified facet
Stats.calcdistinct	Boolean values that will return "countdistinct" and "distinctvalues" at a high cost. Default Fasle

Stats Component Statistical content

Statistical Projects	Description	Types of support	whether the default output
Min	Minimum value	All	Is
Max	Maximum Value	All	Is
Sum	And	Numbers, dates	Is
Count	Number	All	Is
Missing	Number of NULL values	All	Is
Sumofsquares	Sum of squares	Numbers, dates	Is
Mean	Mean number, date	Is
StdDev	Standard deviation	Numbers, dates	Is
Percentiles	Accuracy/Several decimal places	Digital	Whether
Distinctvalues	set/non-repeating value collection	All	Whether
CountDistinct	Set exact number/non-repeating value collection size, very expensive to use	All	Whether
Cardinality	Set number/non-repeating value collection size, may not be accurate	All	Whether

The following query:

http://localhost:8983/solr/solr_select/select?q=*:* &stats=true&stats.field=id&rows=0&indent= True