Aggregation On Struct columns Hive
select t.name ,count (e.col.n_nationkey) as count ,sum (e.col.n_nationkey) as sum ,count (distinct e.col.n_nationkey) as distinct_val from temp t lateral view explode (t.nations) egroup by t.name order by t.name;For the OP
The same solution with an alias.nations is not a struct. It is an array of structs.
It does not have an n_nationkey attribute. It has struct elements that have n_nationkey attributes.
The explode function takes an array of structs (nations) and return each struct (nation) in a separate row.
select t.name ,count (e.nation.n_nationkey) as count ,sum (e.nation.n_nationkey) as sum ,count (distinct e.nation.n_nationkey) as distinct_val from temp t lateral view explode (t.nations) e as nationgroup by t.name order by t.name;