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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -2,7 +2,7 @@ This is a super basic beginners guide to Solr Lucene query syntax. We're going to cover running a straightforward query, as well as some of the more useful functionality such as filtering and creating facets. We'll point out some things you can't do and generally give you enough instruction so that you can get yourself into trouble. #### For testing you need a REST client capable of sending requests to your Solr instance. Either [RESTClient](http://restclient.net/) for Firefox or [Postman](https://chrome.google.com/webstore/detail/postman-rest-client/fdmmgilgnpjigdojojpjoooidkmcomcm?hl=en) for Chrome are good choices. ### Misc -
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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,152 @@ # Solr Query Syntax Basics This is a super basic beginners guide to Solr Lucene query syntax. We're going to cover running a straightforward query, as well as some of the more useful functionality such as filtering and creating facets. We'll point out some things you can't do and generally give you enough instruction so that you can get yourself into trouble. ### This guide assumes you have a REST client capable of sending requests to your Solr instance. Either [RESTClient](http://restclient.net/) for Firefox or [Postman](https://chrome.google.com/webstore/detail/postman-rest-client/fdmmgilgnpjigdojojpjoooidkmcomcm?hl=en) for Chrome are good choices. ### Misc #### Request Specific Fields To specify a list of fields to return instead of the default Solr response use <code>fl</code> and provide a comma delimited list of fields: ```url &fl=ss_destination,fs_total_price,ds_departure_date ``` #### Limit Number of results To specify the number of results to return include the <code>rows</code> parameter with a numeric value: ```url &rows=10 ``` This can be combined with the <code>start</code> value to creating pagination queries: ```url &rows=10&start=0 ... &rows=10&start=10 ``` ### Query String To provide Apache Solr with a query string to search on you must use the <code>q</code> parameter like so: ```url q='Cruises' ``` You can also use <code>AND</code> as well as <code>OR</code> in this string to create boolean queries. ```url q='Athens OR United Kingdom' ... q='Athens AND Istanbul' ``` ### Filter Queries Filter queries are used to narrow the results of a search and are normally used to restrict the search based on the value of specific fields that have been indexed. Multiple filter queries can be added to the same base query, each is run in turn against the results of the previous query. This allows you to have some pre-made filter queries that you can programmatically apply to the query as needed and they will all work in tandem. The basic structure of a filter query is as follows: ```url &fq=<field_id>:<query> ... &fq=ss_destination:(Bali) ``` Filter queries also support the use of wildcards <code>*</code> to create _STARTS WITH_, _CONTAINS_, or _ENDS WITH_ style queries: ```url &fq=ss_destination(Bali*) ... &fq=ss_destination(*Bali*) ... &fq=ss_destination(*Bali) ``` Filter queries can be combined as well to create more complex boolean filter conditions. Be sure to include <code>()</code> around the items: ```url &fq=(ss_destination(Bali) OR ss_destination:(Sydney)) ... &fq=(ss_destination(Bali) AND ss_one_way:(Yes)) ``` ### Ranges _BETWEEN_ Filter queries also support the use of _ranges_ to filter for any results that occur between set boundaries. ```url &fq=fs_total_price:[<min> TO <max>] ... &fq=fs_total_price:[100 TO 999] ... &fq=fs_total_price:[1 TO *] ... &fq=fs_total_price:[* TO 999] ``` ### Negate Operator Any filter query can have a _negate_ operator applied to them to set this filter query to a _NOT_ matching style filter. You simply prepend the <code>-</code> to the start of your field name to declare this as a _NOT_ filter. ```url &fq=-fs_total_price:[1000 TO *] ... &fq=-ss_destination:(Bali) ``` These can be included in combined filter queries as well. ```url &fq=(ss_destination:(Bali) AND -fs_total_price:[1000 TO *]) ``` ### Facets To request [facets](http://wiki.apache.org/solr/SimpleFacetParameters) from Solr you first need to tell Solr to activate them for this particular query, without this there will be no facet results: ```url &facet=true ``` After which you must specify fields to provide faceted results for using the <code>facet.field</code> parameter: ```url &facet=true&facet.field=<field_id> ... *facet=true&facet.field=ss_destination ``` This will add a facet section to the query response and the facet results will include the number of results for each entry in the faceted field. This basic usage will return results even if there are zero results for any of the facets. So if you have no indexed entries for a specific field that you request a facet for, that entry will still appear however it will show a count of _0_. To eliminate these results you can add the <code>facet.mincount</code> to the query to specify the minimum number of results that each facet must have before it will be included. ```url &facet=true&facet.field=ss_destination&facet.mincount=1 ``` Setting it to _1_ will eliminate any zero result facets from the query result. To specify facet results for multiple fields, add multiple <code>facet.field</code> parameters to the query string: ```url &facet=true&facet.field=ss_destination&facet.field=fs_total_price&facet.mincount=1 ``` ### Facet Ranges In the final example above we included a facet field for the _fs\_total\_price_, this would create a facet where there was an entry for every unique value that is indexed in the _fs\_total\_price_ field. This could create an unwieldy facet result which doesn't add much value as it is too granular. In this case we need to create a facet that creates a set of result ranges based on your specifications. The main components required to create a ranged facet are: * <code>facet.range</code> which takes a field id as its value * <code>f.<field_id>.facet.range.start</code> to indicate what the starting value of the range is. A complete entry would look like: <code>f.fs_total_price.facet.range.start</code>. * <code>f.<field_id>.facet.range.end</code> to indicate where the range ends. This is the final value in the range. It works the same as the facet.range.start value. * <code>f.<field_id>.facet.range.gap</code> specifies the _step_ value for the range. It is a numeric value that indicates the distance between each facet result. A complete facet range for our _fs\_total\_price_ field that went from 200 to 3000 in increments of 500 would look like this: ```url &facet=true&facet.field=fs_total_price&facet.range=fs_total_price&f.fs_total_price.facet.range.start=200&f.fs_total_price.facet.range.end=3000&f.fs_total_price.facet.range.gap=500 ``` Note that a facet range query such as the one above will exclude and result that is below 200 or above 3000 in the facet result. This may be desired behaviour but if you would like to include this information in the facet then you need to include the <code>facet.range.include</code> parameter. All of its options are [here](http://wiki.apache.org/solr/SimpleFacetParameters#facet.range.include). #### You may include multiple ranges for different fields on the one query, but they must be for different fields. You cannot have multiple ranges on one field in a single query. Or at least I haven't worked out how to do it. #### You cannot create facet ranges for fields that are multivalue. ### Sorting To sort a Solr query you must supply a field ID and a sort direction. You can specify multiple sort parameters and each one will be applied in turn: ```url &sort=fs_total_price asc ... &sort=fs_total_price asc&sort=fs_number_of_travellers desc ``` #### You cannot sort on fields that are multivalue fields. ### Grouping You are able to create groups of results in a Solr query, depending on your query this is a way of aggregating results into _sections_. Adding the <code>group</code> parameters to your query will group _all_ results. You need to first tell Solr that you are going to specify group information by setting <code>group</code> to true, then you need to specify a field to group on using <code>group.field</code> with a value of the field ID. ```url &group=true&group.field=ss_destination ```