将一个表连接到一个对我来说太复杂的 SQL 查询

Question

我不是很精通 MySQL 查询，而且我通常只做非常简单的 JOIN。我正在安装 osCommerce，我希望类别页面也包含所有子类别的产品。

select
    p.products_image,
    pd.products_name,
    pd.products_description,
    p.products_id,
    p.manufacturers_id,
    p.products_price,
    p.products_tax_class_id,
    IF(s.status, s.specials_new_products_price, NULL) as specials_new_products_price,
    IF(s.status, s.specials_new_products_price, p.products_price) as final_price
from
    products_description pd,
    products p
left join
    manufacturers m on p.manufacturers_id = m.manufacturers_id
left join
    specials s on p.products_id = s.products_id,
    products_to_categories p2c
where
    p.products_status = '1' and
    p.products_id = p2c.products_id and
    pd.products_id = p2c.products_id and
    pd.language_id = '1' and
    (p2c.categories_id = '24' or ###.parent_id = '24')
order by pd.products_name asc

基本上，我还需要将类别表加入到此查询中，从类别表中的 category_id = p2c.categories_id 中提取行。然后，我可以从类别表中的选定行中引用 parent_id 列（我会将上面的“###”替换为“cat”之类的内容）。

但是，我对所有左连接感到困惑，我应该在哪里插入另一个 JOIN 子句。

任何帮助将不胜感激。

谢谢！

Answer 1

没有要测试的表，但应该像这样简单；

SELECT
    p.products_image,
    ...
FROM products_description pd
JOIN products p
  ON pd.products_id = p.products_id
LEFT JOIN manufacturers m 
  ON p.manufacturers_id = m.manufacturers_id
LEFT JOIN specials s 
  ON p.products_id = s.products_id
JOIN products_to_categories p2c
  ON p2c.products_id = p.products_id
JOIN categories c
  ON c.categories_id = p2c.categories_id
WHERE
    p.products_status = '1' and
    pd.language_id = '1' and
    (p2c.categories_id = '24' or c.parent_id = '24')
ORDER BY by pd.products_name ASC