Question

我有几张桌子：型号，产品，规格，图片和商店它们的关联如下：

每个产品属于（型号，商店）
每张图片属于（产品）
每个规范都属于（产品）

我需要一份产品清单，

与他们所属的商店（by product.store_id）
    product.model_id = some_id
    仅在有产品规格的情况下（按spec.product_id）     仅当产品有图片时（通过picture.product_id）

我需要什么类型的查询？

感谢

Answer 1

您的定义非常完整，可以完全按字面翻译：

select
  -- Selecting all fields of product and store. 
  -- You can refine this by only listing the fields you need.
  p.*,
  s.*
from
  -- need a list of products,
  product p
  -- with the store they belongs to (by product.store_id)
  inner join store s on s.store_id = p.store_id
where
  -- ONLY if there are specs for the product (by spec.product_id)
  exists
    (select
      'x'
    from
      spec ps 
    where
      ps.product_id = p.product_id) and
  -- ONLY if a product has pictures (by picture.product_id)
  exists
    (select
      'x'
    from
      pictures pp 
    where
      pp.product_id = p.product_id)

Answer 2

试试这个::

Select * from 
from 
product p
inner join model m on (p.model_id=m.id)
inner join store s on (p.store_id=s.id)
inner join picture pc on (p.picture_id=pc.id)
inner join spec sp on (p.spec_id=sp_id)

where product.model_id=some_id
GROUP BY product.id

mysql如何加入这些表？

2 个答案: