How to Compare Arrays in PostgreSQL

The equality operators (=, <>) do an exact element-by-element comparison.

array[1,2,3] = array[1,2,4] as compare1, -- arrays are equal
array[1,2,3] <> array[1,2,4] as compare2; -- arrays are not equal
compare1 compare2
John 1.85
Mary 1.65

The ordering operators (>, <, >=, <=) also compare each element in an array in order. Results are based on the first different pair of elements, not the sizes of the arrays.

array[1,2,5] >= array[1,2,4] as compare1,
array[1,2,5] <= array[1,2,4,5] as compare2;
compare1 compare2
t f

Then there are the containment operators (@>, <@). They are casually called “bird operators”, well, because @> looks like a bird. An array is said to be contained in another array if each of its unique elements is also present in the other array.

-- This reads as array['a', 'b', 'c'] contains array['a', 'b', 'b', 'a']
select array['a', 'b', 'c'] @> array['a', 'b', 'b', 'a'] as contains;
-- This reads as array[1, 1, 4] is contained by array[4, 3, 2, 1]
select array[1, 1, 4] <@ array[4, 3, 2, 1] as is_contained_by;

Lastly, there is the overlap operator (&&). Arrays that have elements in common are called overlapping arrays. To check if two arrays overlap, use the && operator:

array[1, 2] && array[2, 3] as overlap1,
array[1, 2] && array[3, 4] as overlap2;
overlap1 overlap2
t f