ExAliyunOts.Search.exists_query
You're seeing just the function
exists_query, go back to ExAliyunOts.Search module for more information.
Specs
exists_query(field_name()) :: map()
Use ExistsQuery as the nested :query option of :search_query option in ExAliyunOts.search/4.
Official document in Chinese | English
Example
import MyApp.TableStore
search "table", "index_name",
search_query: [
query: exists_query("values")
]