sql - 如果没有找到结果，SQL 返回行

Question

我有两张桌子：

person
id
name

car
name
person_id

目前查询如下：

SELECT
person.name
car.name
FROM
person, car
WHERE
person.id = car.person_id

现在，如果有一辆车与一个人相关联，这可以正常工作。但是，如果没有，则该人将不会被退回。如果一个人没有车，我想用'No Car'column中的文本返回一行car.name。

Answer 1

select person.name, coalesce(car.name, 'no car')
from person
left outer join car on person.id = car.person_id

Answer 2

SELECT person.name, CASE WHEN car.name IS NULL THEN 'no car' ELSE car.name END 
FROM person
LEFT JOIN car ON person.id = car.person_id

Answer 3

select person.name, ISNULL(car.name, 'no car')
from person
left join car on person.id = car.person_id