postgres: How to count distinct elements in array columns given a condition
select id, count(distinct a1) as a1, count(distinct a2) as a2from ( select id, unnest(array1) as a1, unnest(array2) as a2 from t) sgroup by id
select id, count(distinct a1) as a1, count(distinct a2) as a2from ( select id, unnest(array1) as a1, unnest(array2) as a2 from t) sgroup by id