假设我有下表:
品牌表
+-----------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| ID | varchar(20) | NO | PRI | NULL | |
| CarBrand | varchar(100) | NO | | NULL | |
| FuelType | varchar(100) | NO | | NULL | |
+-----------+--------------+------+-----+---------+-------+
模型表
+------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| ID | int(2) | NO | | NULL | |
| Model | varchar(100) | NO | | NULL | |
| BrandID | varchar(100) | NO | MUL | NULL | |
| TopSpeed | varchar(100) | NO | | NULL | |
+------------+--------------+------+-----+---------+-------+
这里有一些条目
+----+----------------+-------------------------+
| ID | CarBrand | FuelType |
+----+----------------+-------------------------+
| 0 | Ford | Gasoline |
| 1 | Chevy | Gasoline |
| 2 | Peterbilt | Diesel |
| 3 | GMC | Gasoline |
| 4 | OshKosh | Natural Gas |
+----+----------------+-------------------------+
+----+---------------+---------+------------+
| ID | Model | BrandID | TopSpeed |
+----+---------------+---------+------------+
| 1 | F150 | 0 | 130MPH |
| 2 | 1500 | 1 | 110MPH |
| 3 | 389 | 2 | 70MPH |
| 4 | 1500 | 3 | 110MPH |
| 5 | Mustang | 0 | 170MPH |
| 6 | Cement Truck | 4 | 65MPH |
+----+---------------+---------+------------+
型号表中的 BrandID 列是品牌表主键 ID 列的外键。如果您无权访问任一列的值怎么办？我将如何编写一个 SQL 查询来使用 INNER JOIN 列出属于 Ford 的所有模型
最佳答案
没有访问 ID，这意味着您只有我猜的型号名称。 所以知道“ford”你就可以得到像这样的两个ID...
select * from modelsTable Mod inner join brandsTable Bra
on Mod.id= ( select id from Bra where CarBrand='FORD')
关于mysql - 在两个表上使用内连接，外键引用主表上的主 ID，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20430039/