简单的MySQL查询，ON JOINS

Question

我有两个表，Car表和Driver表。

在“驱动程序”表中，有name，birthDate和id。 在Car表格中有regNo，manuID，colour，price和driverID。

driverID和id 匹配，但有一个Driver.id不在Car.driverID

我怎样才能只显示Car表中没有的那个。

我试过了：

SELECT id FROM Driver JOIN Car ON Car.driverID!=Driver.id;

Answer 1

您可以使用子查询。

SELECT id FROM Driver WHERE id not in (select distinct driverid from car)

Answer 2

你可以这样做

SELECT * FROM `driver` WHERE `id` not in(select `driverId` from `car`)

Answer 3

尝试

SELECT c.*
FROM Cars AS C
LEFT JOIN Drivers AS D ON d.id=c.driverId
WHERE d.id IS NULL

Answer 4

如果你想使用join，那么你可以这样做：

SELECT d.id
FROM Driver d
LEFT JOIN Car c ON (d.id=c.driverID)
WHERE c.driverID is NULL;

您还可以查看this answer了解其他方法。