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Elasticsearch documentation suggests* that their piece of code
*documentation fixed
GET /cars/transactions/_search?search_type=count { "aggs": { "distinct_colors": { "cardinality": { "field": "color" } } } } corresponds to sql query
SELECT DISTINCT(color) FROM cars but it actually corresponds to
SELECT COUNT(DISTINCT(color)) FROM cars I don't want to know how many distinct values I have but what are the distinct values. Anyone knows how to achieve that?
848
You can user terms aggregation to get distinct values from your _source. As you have mentioned you don't want any other data from _source hence you can give size=0. This will give you all unique Gender values with their count in the response.
List<int> myList = list. Distinct(). ToList();
Elasticsearch Aggregations Cardinality AggregationA single-value metrics aggregation that calculates an approximate count of distinct values. Values can be extracted either from specific fields in the document or generated by a script.
SQL DISTINCT clause is used to remove the duplicates columns from the result set. The distinct keyword is used with select keyword in conjunction. It is helpful when we avoid duplicate values present in the specific columns/tables. The unique values are fetched when we use the distinct keyword.
Use a terms aggregation on the color field. And you need to pay attention to how that field you want to get distinct values on is analyzed, meaning you need to make sure you're not tokenizing it while indexing, otherwise every entry in the aggregation will be a different term that is part of the field content.
If you still want tokenization AND to use the terms aggregation you might want to look at not_analyzed type of indexing for that field, and maybe use multi fields.
Terms aggregation for cars:
GET /cars/transactions/_search?search_type=count { "aggs": { "distinct_colors": { "terms": { "field": "color", "size": 1000 } } } } To update the excellent answer from Andrei Stefan, we need to say that the query parameter search_type=count is no more supported in Elasticsearch 5. The new way of doing this is to add "size" : 0 in the body such as :
GET /cars/transactions/_search { "size": 0, "aggs": { "distinct_colors": { "terms": { "field": "color", "size": 1000 } } } } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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