Function diesel::dsl::count_distinct
source · pub fn count_distinct<T, E>(expr: E) -> CountDistinct<T, E::Expression>
Expand description
Creates a SQL COUNT(DISTINCT ...)
expression
As with most bare functions, this is not exported by default. You can import
it specifically as diesel::dsl::count_distinct
, or glob import
diesel::dsl::*
§Examples
let unique_user_count = posts.select(count_distinct(user_id)).first(connection);
assert_eq!(Ok(2), unique_user_count);