php - SQL 连接 : I cant show a list of categories

Question

我试图根据它收到的规范表值在“规范”列表中显示表格的所有“汽车”。

表格:

汽车:

dcar: 1 / width:30 / length:10 / weight:300
idcar: 2 / width:20 / length:12 / weight:210
idcar: 3 / width:20 / length:21 / weight:230
idcar: 4 / width:40 / length:11 / weight:210

规范表:

idspec:1 spec:width
idspec:2 spec:weight
idspec:3 spec:length

输出将是:

Width
car-1 width-30
car-2 width-20
car-3 width-20
car-4 width-40


Weight
car-1 weight-300
car-2 weight-210
car-3 weight-230
car-4 weight-210

Length
car-1 length-10
car-2 length-12
car-3 length-21
car-4 length-11

我的查询可以吗？我想在一段时间内使用它或 foreach (php)

$resultjoin = mysqli_query($connecDB,"SELECT specs.idspec, specs.spec, cars.idcar FROM (specs) LEFT JOIN cars ON cars.idcar = specs.idspec");

谢谢!

Answer 1

试试这个

您的表格设计有误。在 spec 和 car 之间还有另一个表。比如 car_apec_value 会有 carid, specid, value。

通过加入这三张 table ，您将获得您想要的结果，例如

$resultjoin = mysqli_query($connecDB,"SELECT 'cars'.'idcar', 'specs'.'spec' FROM cars LEFT JOIN car_apec_value ON cars'.idcar = 'car_apec_value'.'carid' where specs.specid = car_apec_value.specid AND specs.specid='1'");