先来看两个查询语句:
SELECT customer_id,
rental_id,
return_date
FROM
rental
WHERE
customer_id IN (1, 2)
ORDER BY
return_date DESC;
SELECT
rental_id,
customer_id,
return_date
FROM
rental
WHERE
customer_id = 1 OR customer_id = 2
ORDER BY
return_date DESC;
两个查询语句返回的结果是相同的,但是IN的执行要比 OR或者AND快很多,所以更推荐第一种写法。
NOT IN表示不在某个范围
IN后边可以是子查询返回的值的列表