Sorting and paging

Single-field sort

Sorts results based on the values in a single field.

SearchQuery searchQuery = new SearchQuery();
searchQuery.setSort(new Sort(Arrays.asList(new FieldSort("col", SortOrder.ASC))));

Multi-field sort

Sorts results first by the values in one field, and then by the values in another field.

SearchQuery searchQuery = new SearchQuery();
searchQuery.setSort(new Sort(Arrays.asList(
    new FieldSort("col1", SortOrder.ASC), new FieldSort("col2", SortOrder.ASC))));

Fallback field

When you sort by a field of the Long, Double, or Date type, you can set the missingField parameter. This parameter specifies another field of the same type to use as a fallback value for sorting if a row is missing a value in the primary sort field.

/**
* Sort results in descending order based on the values in the Col_Long field. 
* If a row is missing a value in the Col_Long field (Long type), 
* the value from the Col_Long_sec field (Long type) is used for sorting instead.
*/
SearchQuery searchQuery = new SearchQuery();
FieldSort fieldSort = new FieldSort("Col_Long");
// Specify the Col_Long_sec field as the fallback for sorting when a value is missing in the Col_Long field.
fieldSort.setMissingField("Col_Long_sec");
fieldSort.setOrder(SortOrder.DESC); 

Missing values

The missingValue parameter specifies the sort position for documents that are missing the sort field. You can set this parameter to control where these documents appear in the results.

The sorting behavior is as follows:

• If you set missingValue to FieldSort.FIRST_WHEN_MISSING, documents with missing values are always placed at the beginning of the results, regardless of the sort order (ascending or descending).

• If you set missingValue to FieldSort.LAST_WHEN_MISSING or null, documents with missing values are always placed at the end of the results, regardless of the sort order.

  /**
  * Sort results in descending order based on the values in the Col_Long field (Long type).
  * If a row is missing a value in the Col_Long field, place that document at the beginning of the results.
  */
  SearchQuery searchQuery = new SearchQuery();
  FieldSort fieldSort = new FieldSort("Col_Long");
  // Place documents with missing values first.
  fieldSort.setMissingValue(FieldSort.FIRST_WHEN_MISSING);
  fieldSort.setOrder(SortOrder.DESC);
  searchQuery.setSort(new Sort(Arrays.asList(fieldSort)));

Multi-valued fields

For multi-valued fields, such as array type or nested type fields, you can use the mode parameter to specify which element to use for sorting.

Sort by a specified value in a multi-valued array.

// Assume you have two rows, doc1 and doc2. Both have a field1 of array type.
// The value of field1 in doc1 is [2,3]. The value of field1 in doc2 is [1,3,4].
// You can set the mode parameter to specify which value in the array to use for sorting.
{
    // When mode is set to SortMode.MAX, the sort order is doc2 (sorted by 4), then doc1 (sorted by 3).
    FieldSort fieldSort = new FieldSort("field1", SortOrder.DESC);
    fieldSort.setMode(SortMode.MAX);
}
{
    // When mode is set to SortMode.MIN, the sort order is doc1 (sorted by 2), then doc2 (sorted by 1).
    FieldSort fieldSort = new FieldSort("field1", SortOrder.DESC);
    fieldSort.setMode(SortMode.MIN);
}

You can also sort the sub-rows of a nested type field.

// Assume you have two rows, doc1 and doc2. Both have a field1 of nested type.
// The value of field1 in doc1 is [{"name":"b", "age":1},{"name":"a", "age":7}].
// The value of field1 in doc2 is [{"name":"a", "age":1},{"name":"c", "age":1},{"name":"d", "age":5}].

{
    // Sort all sub-rows and use the mode parameter to specify which value to use for sorting.
    // When mode is set to SortMode.MAX and you sort by the age field, the result is doc1 (sorted by 7), then doc2 (sorted by 5).
    FieldSort fieldSort = new FieldSort("field1.age", SortOrder.DESC);
    fieldSort.setMode(SortMode.MAX);
    String path = "field1";
    NestedFilter nestedFilter = new NestedFilter(path, QueryBuilders.matchAll().build());
    fieldSort.setNestedFilter(nestedFilter);
}
{
    // Sort only the sub-rows where age=1, and use the mode parameter to specify which value to use.
    {
        // When mode is set to SortMode.MAX and you sort by the name field, the result is doc2 (sorted by "c"), then doc1 (sorted by "b").
        FieldSort fieldSort = new FieldSort("field1.name", SortOrder.DESC);
        fieldSort.setMode(SortMode.MAX);
        String path = "field1";
        NestedFilter nestedFilter = new NestedFilter(path, QueryBuilders.term("field1.age",1).build());
        fieldSort.setNestedFilter(nestedFilter);
    }
    {
        // When mode is set to SortMode.MIN and you sort by the name field, the result is doc1 (sorted by "b"), then doc2 (sorted by "a").
        FieldSort fieldSort = new FieldSort("field1.name", SortOrder.DESC);
        fieldSort.setMode(SortMode.MIN);
        String path = "field1";
        NestedFilter nestedFilter = new NestedFilter(path, QueryBuilders.term("field1.age",1).build());
        fieldSort.setNestedFilter(nestedFilter);
    }
}