feat: compare literal

Author: tobyhede

src/encrypted/compare.sql

@@ -0,0 +1,42 @@
+-- REQUIRE: src/schema.sql
+-- REQUIRE: src/encrypted/types.sql
+
+--
+-- Compare two eql_v2_encrypted values as literal jsonb values
+-- Used as a fallback when no suitable search term is available
+--
+CREATE FUNCTION eql_v2.compare_literal(a eql_v2_encrypted, b eql_v2_encrypted)
+  RETURNS integer
+  IMMUTABLE STRICT PARALLEL SAFE
+AS $$
+  DECLARE
+    a_data jsonb;
+    b_data jsonb;
+  BEGIN
+
+    IF a IS NULL AND b IS NULL THEN
+      RETURN 0;
+    END IF;
+
+    IF a IS NULL THEN
+      RETURN -1;
+    END IF;
+
+    IF b IS NULL THEN
+      RETURN 1;
+    END IF;
+
+    a_data := a.data;
+    b_data := b.data;
+
+    IF a_data < b_data THEN
+      RETURN -1;
+    END IF;
+
+    IF a_data > b_data THEN
+      RETURN 1;
+    END IF;
+
+    RETURN 0;
+  END;
+$$ LANGUAGE plpgsql;