create hive table and find total NULL fields in each column

Question

I need to write a query that returns number of null fields in every column in a hive table

eg:

col1|col2|col3
----------------
NULL|a   |b
NULL|a   |b
e   |NULL|f

the query should return 2 1 0 for the above table. Someone help please??

Answer 1

select
sum(if(col1 is null, 1, 0)),
sum(if(col2 is null, 1, 0)),
sum(if(col3 is null, 1, 0))
from mytable