PostgreSQL check if array contains any element from left-hand array

Question

I know that in PostgreSQL you can run a query like:

SELECT (1 = ANY('{1,3,4,7}'::int[])) AS result to check if the right-hand array contains the element 1. I was wondering if there is an easy way to check if the right-hand array contains any element from the left-hand array. Something like:

SELECT ('{2,3}'::int[] = ANY('{1,3,4,7}'::int[])) AS result

Is there an easy way to do this without iterating over the left-hand loop myself?

Answer 1

Sure, use the && array-overlaps operator:

SELECT ARRAY[1,2] && ARRAY[1,3,4,7];

See array functions and operators.

Answer 2

Assuming that your inputs are arrays but it is okay to unwrap them using unnest(), here is a solution:

SELECT count(*)>0
FROM
    (SELECT unnest('{2,3}'::int[]) a1) t1
    join (SELECT unnest('{1,3,4,7}'::int[]) a2) t2
        on t1.a1=t2.a2;