How to query for terms IN a collection using Lucene.Net, similar to SQL's IN operator?

Question

We are trying to search whether documents have a particular field value in a collection of possible values,

field:[value1, value2, value3, ..., valueN]

which would return the element if it matches any of the input values, similar to SQL's IN() operator.

This would be similar to a range query, but the elements do not necessarily describe a range.

An example using Lucene.Net API would be,

var query = new QueryParser(version, "FieldName", analyzer).In("value1", "value2", "value3");

Is this possible in Lucene.Net?

Answer 1

field:value1 field:value2 .... should do the trick. By default all terms are ORed.

Programmatically, you can try,

public static Query In(string fieldName, IEnumerable<string> values)
{
    var query = new BooleanQuery();
    foreach (var val in values)
    {
        query.Add(new TermQuery(new Lucene.Net.Index.Term(fieldName, val)), BooleanClause.Occur.SHOULD);
    }
    return query;
}

Answer 2

As @I4V mentioned, Lucene ORs terms by default, so this should give you the wanted result,

public Query In(string propertyName, IEnumerable<string> collection)
{
    var query = new QueryParser(version, propertyName, analyzer).Parse(string.Join(" ", collection));

    return query;
}

based on,

field:value1, value2, value3, ..., valueN

will return any document with at least one value in the collection.