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javamavenspring-mvcsolr

Sort the search result in ascending order of a multivalued field in Solr

I'm using Solr of version 6.6.0. I have a schema of title (text_general), description(text_general), id(integer). When I search for a keyword to list the results in ascending order of the title my code returns an error can not sort on multivalued field: title.

I have tried to set the sort using the following 3 methods

SolrQuery query = new SolrQuery();
1. query.setSort("title", SolrQuery.ORDER order);
2. query.addSort("title", SolrQuery.ORDER order);
3. SortClause ab = new SolrQuery.SortClause("title", SolrQuery.ORDER.asc);
   query.addSort(ab);

but all of these returns the same error

I found a solution by referring to this answer

It says to use min/max functions. query.setSort(field("pageTitle",min), ORDER.asc); this what I'm trying to set as the query, I didn't understand what are the arguments used here.

This is the maven dependency that I'm using 

<dependency>
    <groupId>org.apache.solr</groupId>
    <artifactId>solr-solrj</artifactId>
    <version>6.5.1</version>
</dependency>
Solution

  • Unless title actually is multiValued - can your post have multiple titles - you should define it as multiValued="false" in your schema. However, there's a second issue - a field of the default type text_general isn't suited for sorting, as it'll generate multiple tokens, one for each word in the title. This is useful for searching, but will give weird and non-intuitive results when sorting.

    So instead, define a title_sort field and use a field type with a KeywordTokenizer and LowerCaseFilter attached (if you want case insensitive sort), or if you want case sensitive sort, use the already defined string field type for the title_sort field.