Ajuda com Atividade prática de banco de dados

UPDATE employees
SET EMAIL='CANCELADO'
WHERE DEPARTMENT_ID='60'

** Não tenho certeza se está certo

acho q não.

O algoritmo será:

DO $$

DECLARE

v_ts TIMESTAMP;

v_repeat CONSTANT INT := 2000;

rec RECORD;

BEGIN

-- Repeat benchmark several times to avoid warmup penalty

FOR r IN 1..5 LOOP

v_ts := clock_timestamp();

FOR i IN 1..v_repeat LOOP

FOR rec IN (

SELECT * FROM film WHERE length = 120

) LOOP

NULL;

END LOOP;

END LOOP;

RAISE INFO 'Run %, Statement 1: %', r,

(clock_timestamp() - v_ts);

v_ts := clock_timestamp();

FOR i IN 1..v_repeat LOOP

FOR rec IN (

WITH r AS (

SELECT * FROM film WHERE length = 120

)

SELECT * FROM r

UNION ALL

SELECT * FROM film

WHERE length = 130

AND NOT EXISTS (

SELECT * FROM r

)

) LOOP

NULL;

END LOOP;

END LOOP;

RAISE INFO 'Run %, Statement 2: %', r,

(clock_timestamp() - v_ts);

RAISE INFO '';

END LOOP;

END$$;