Question

我正在研究电子商务解决方案，我需要一些关于SQL查询的帮助。

我有这样的数据库设计。这是实例

我正在使用此查询

SELECT p.id as product_id, p.name as product_name, 
    pv.name AS Varient_name, pvo.name AS Varient_Option_Name, pvoc.sku_id 
FROM p p 
LEFT JOIN pv pv ON (pv.p_id = p.id) 
LEFT JOIN pvo pvo ON (pvo.pv_id = pv.id) 
LEFT JOIN pvoc pvoc ON (pvoc.pvo_id = pvo.id)

此查询显示此类记录

我想要一个显示如下记录的查询：

这里有人可以帮忙吗？等待谢谢

Answer 1

您正在寻找的是表转置或转轴。

此查询为您执行此操作：

http://sqlfiddle.com/#!9/6d667/80

实际查询：

SELECT
  p.id,
  p.name,
  MAX(CASE WHEN pv.name = 'Size' THEN pvo.name END) AS Size,
  MAX(CASE WHEN pv.name = 'Color' THEN pvo.name END) AS Color,
  MAX(CASE WHEN pv.name = 'Fabric' THEN pvo.name END) AS Fabric,
  pvoc.sku_id,
  COUNT(*) AS Quantity
FROM p AS p
LEFT JOIN pv AS pv
  ON pv.p_id = p.id
LEFT JOIN pvo AS pvo
  ON pvo.pv_id = pv.id
LEFT JOIN pvoc AS pvoc
  ON pvoc.pvo_id = pvo.id
WHERE p.id = 1
GROUP BY p.id, p.name, pvoc.sku_id;

SQL Fiddle的结果：

| id |       name |  Size |  Color | Fabric |                     sku_id | Quantity |
|----|------------|-------|--------|--------|----------------------------|----------|
|  1 | Men Hoodie |    XL | (null) | (null) |                     (null) |        2 |
|  1 | Men Hoodie |     M |  Black | Cotton | MH-Size-M-Color-B-Fabric-C |        3 |
|  1 | Men Hoodie |     M |  Black |  Jersy | MH-Size-M-Color-B-Fabric-J |        3 |
|  1 | Men Hoodie |     M |  White | Cotton | MH-Size-M-Color-W-Fabric-C |        3 |
|  1 | Men Hoodie |     M |  White |  Jersy | MH-Size-M-Color-W-Fabric-J |        3 |
|  1 | Men Hoodie | Small |  Black | Cotton | MH-Size-S-Color-B-Fabric-C |        3 |
|  1 | Men Hoodie | Small |  Black |  Jersy | MH-Size-S-Color-B-Fabric-J |        3 |
|  1 | Men Hoodie | Small |  White | Cotton | MH-Size-S-Color-W-Fabric-C |        3 |
|  1 | Men Hoodie | Small |  White |  Jersy | MH-Size-S-Color-W-Fabric-J |        3 |

不知道为什么第一行有一个NULL值，但我刚刚使用了你给我们的小提琴，它已经有了一个NULL：）

现在你需要做的是 - 标准化尺寸名称（例如Small = S，Large = L），就是这样。

Answer 2

尝试这样的事情，它可能会给你更多的成长空间和更少的冗余： http://sqlfiddle.com/#!9/361d7/1

查询：

SELECT cloth.name, color.name, fabric.name, size.name, connect_all.id_sku, connect_all.quantity
FROM connect_all
LEFT JOIN cloth 
ON cloth.id = connect_all.id_cloth
LEFT JOIN color
ON color.id = connect_all.id_color
LEFT JOIN fabric
ON fabric.id = connect_all.id_fabric
LEFT JOIN size
ON size.id = connect_all.id_size

Answer 3

http://sqlfiddle.com/#!9/6d667/201，您去了！

select p.id, p.name,
max(case when pv.name = 'size' then pvo.name end) as sizes,
max(case when pv.name = 'fabric' then pvo.name end) as fabrics,
max(case when pv.name = 'color' then pvo.name end) as çolours,
sku_id, count(*) as Qty

from p inner join pv
on p.id = pv.p_id
inner join pvo
on pv.id = pvo.pv_id
inner join pvoc
on pvo.id = pvoc.pvo_id
group by p.id, p.name,sku_id;

电子商务数据库查询将行显示为列

3 个答案: