Check if NULL exists in Postgres array

Question

Similar to this question, how can I find if a NULL value exists in an array?

Here are some attempts.

SELECT num, ar, expected,
  ar @> ARRAY[NULL]         


        

Answer 1

I use this

select 
    array_position(array[1,null], null) is not null

array_position - returns the subscript of the first occurrence of the second argument in the array, starting at the element indicated by the third argument or at the first element (array must be one-dimensional)