postgresql - How to compare two arrays and pick only the non matching elements In postgres

Question

How can I pick only the non matching elements between two arrays.

Example:

base_array [12,3,5,7,8]
temp_array [3,7,8]

So here I want to compare both the arrays and remove the matching elements from the base array.

Now base_array should be like [12,5]

Answer 1

I'd approach this with the array operator.

select array(select unnest(:arr1) except select unnest(:arr2));

If :arr1 and :arr2 don't intersect, using array_agg() leads to a null.