Family Day update

Task/Fibonacci-sequence/PL-pgSQL/fibonacci-sequence-3.sql

@@ -0,0 +1,17 @@
+CREATE OR REPLACE FUNCTION fibLinear(n INTEGER) RETURNS INTEGER AS $$
+DECLARE
+  prevFib INTEGER := 0;
+  fib INTEGER := 1;
+BEGIN
+  IF (n < 2) THEN
+    RETURN n;
+  END IF;
+
+  WHILE n > 1 LOOP
+    SELECT fib, prevFib + fib INTO prevFib, fib;
+    n := n - 1;
+  END LOOP;
+
+  RETURN fib;
+END;
+$$ LANGUAGE plpgsql;