How to select distinct field values using Solr?

Question

I would like to do the equivalent of this SQL but with Solr as my data store.

SELECT
   DISTINCT txt
FROM
   my_table;

What syntax would fo

Answer 1

Solr 5.1 and later has the new Facet Module that has integrated support for finding the number of unique values in a field. You can even find the number of unique values in a field for each bucket of a facet, and sort by that value to find the highest or lowest number of unique values.

Number of unique values in "myfield": json.facet={x:'unique(myfield)'}

Facet by "category" field, and for each category, show the number of unique values in "color":

json.facet={
  cat_breakdown : { terms : {  // group results by unique values of "category"
    field : category,
    facet : {
      x : "unique(color)",  // for each category, find the number of unique colors
      y : "avg(price)"      // for each category, find the average price
    }
  }}
}

This is in Solr 5.1 and later. More facet functions like "unique" are shown at http://yonik.com/solr-facet-functions/