I want to make a visualization using Timelion.
I want to plot the count of documents only where a field is unique. In my case it is the user_id of the user.
How do I put the condition that some field should be unique in Timelion expression ?
Hello,.es(*, metric='cardinality:user_id')
Thank you. It was helpful.
It's a term commonly used in SQL for counting the number of unique elements in a set.
In SQL (Structured Query Language), the term cardinality refers to the uniqueness of data values contained in a particular column (attribute) of a database table. The lower the cardinality, the more duplicated elements in a column. Thus, a column with the lowest possible cardinality would have the same value for every row. SQL databases use cardinality to help determine the optimal query plan for a given query. When dealing with columnar value sets, there are three types of cardinality: high-car...