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How to query SOLR for empty fields?

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solr

lucene

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How do you directly query Solr?

Trying a basic queryThe main query for a solr search is specified via the q parameter. Standard Solr query syntax is the default (registered as the “lucene” query parser). If this is new to you, please check out the Solr Tutorial. Adding debug=query to your request will allow you to see how Solr is parsing your query.

What is Q in Solr query?

Solr provides Query (q parameter) and Filter Query (fq parameter) for searching. The query (q parameter), as the name suggests, is the main query used for searching. Example. q = title:james. Filter queries are used alongside query (q parameter) to limit results of queries using additional filters.

How do I query in Solr dashboard?

You can search for "solr" by loading the Admin UI Query tab, enter "solr" in the q param (replacing *:* , which matches all documents), and "Execute Query". See the Searching section below for more information. To index your own data, re-run the directory indexing command pointed to your own directory of documents.

What does FQ mean in Solr?

The fq (Filter Query) Parameter The fq parameter defines a query that can be used to restrict the superset of documents that can be returned, without influencing score. It can be very useful for speeding up complex queries, since the queries specified with fq are cached independently of the main query.


Try this:

?q=-id:["" TO *]

One caveat! If you want to compose this via OR or AND you cannot use it in this form:

-myfield:*

but you must use

(*:* NOT myfield:*)

This form is perfectly composable. Apparently SOLR will expand the first form to the second, but only when it is a top node. Hope this saves you some time!


According to SolrQuerySyntax, you can use q=-id:[* TO *].


If you have a large index, you should use a default value

   <field ... default="EMPTY" />

and then query for this default value. This is much more efficient than q=-id:["" TO *]


You can also use it like this.

fq=!id:['' TO *]

If you are using SolrSharp, it does not support negative queries.

You need to change QueryParameter.cs (Create a new parameter)

private bool _negativeQuery = false;

public QueryParameter(string field, string value, ParameterJoin parameterJoin = ParameterJoin.AND, bool negativeQuery = false)
{
    this._field = field;
    this._value = value.Trim();
    this._parameterJoin = parameterJoin;
    this._negativeQuery = negativeQuery;
}

public bool NegativeQuery
{
    get { return _negativeQuery; }
    set { _negativeQuery = value; }
}

And in QueryParameterCollection.cs class, the ToString() override, looks if the Negative parameter is true

arQ[x] = (qp.NegativeQuery ? "-(" : "(") + qp.ToString() + ")" + (qp.Boost != 1 ? "^" + qp.Boost.ToString() : "");

When you call the parameter creator, if it's a negative value. Simple change the propertie

List<QueryParameter> QueryParameters = new List<QueryParameter>();
QueryParameters.Add(new QueryParameter("PartnerList", "[* TO *]", ParameterJoin.AND, true));

you can do it with filter query q=*:*&fq=-id:*