我有以下表格：
products- 包含库存中的产品。suppliers- 包含供应商详细信息。product_category- 包含产品类别的名称。product_suppliers- 包含产品和供应商之间的关系。
这里重要的可能是 , product_suppliers，所以这里是列：
id //(auto-increment)
prod_id //(id of product)
sup_id //(id of supplier)
preferred //(1 if it's the preferred supplier for that product - 0 if not)
cost_per_outer //(this suppliers price for this item)
qty_in_outer //(the number in a box)
该product表在存储产品详细信息的同时，还有一个用于stock_level和的字段reorder_level。当前者小于后者时，该产品应列入重新订购清单。
我正在尝试为列表构建查询，但工作不正常。
我有 4 件商品符合重新订购的条件，影响到两家供应商。每个供应商应该有两个项目，但目前它只检索第一个供应商的结果。
我正在使用 MySQL 和 PHP。
我运行了以下查询，让我们对数据库中的实际数据有一些了解：
mysql> SELECT
-> p.prod_id,
-> AES_DECRYPT(p.alt_id, 'MW4KQLg1Irfo3Xz7Nxht') AS sku,
-> AES_DECRYPT(p.prod_name, 'MW4KQLg1Irfo3Xz7Nxht') AS prod_name,
-> AES_DECRYPT(p.prod_type, 'MW4KQLg1Irfo3Xz7Nxht') AS prod_type,
-> AES_DECRYPT(p.stock_level, 'MW4KQLg1Irfo3Xz7Nxht') AS stock_level,
-> AES_DECRYPT(p.reorder_level, 'MW4KQLg1Irfo3Xz7Nxht') AS reorder_level,
-> AES_DECRYPT(c.category_name, 'MW4KQLg1Irfo3Xz7Nxht') AS category_name,
-> ps.sup_id,
-> ps.preferred
-> FROM
-> products p
-> INNER JOIN
-> product_category c
-> ON
-> p.category_id = c.category_id
-> INNER JOIN
-> product_supplier ps
-> ON
-> p.prod_id = ps.prod_id
-> INNER JOIN
-> suppliers s
-> ON
-> ps.sup_id = s.supplier_id
-> ORDER BY
-> ps.sup_id;
+---------+------+-----------------+-----------+-------------+---------------+---------------+--------+-----------+
| prod_id | sku | prod_name | prod_type | stock_level | reorder_level | category_name | sup_id | preferred |
+---------+------+-----------------+-----------+-------------+---------------+---------------+--------+-----------+
| 7 | 7 | Term Block | 1 | 3 | 5 | Electrical | 2 | 1 |
| 5 | 5 | Electrical Tape | 1 | 12 | 20 | Electrical | 2 | 1 |
| 6 | 6 | BlowGas | 1 | 6 | 15 | Plumbing | 12 | 1 |
| 1 | 1 | PTFE Tape | 1 | 9 | 10 | Plumbing | 12 | 1 |
+---------+------+-----------------+-----------+-------------+---------------+---------------+--------+-----------+
这是列表的查询，结果只显示了我期望的四个项目中的两个：
mysql> SELECT
-> p.prod_id,
-> AES_DECRYPT(p.alt_id, 'MW4KQLg1Irfo3Xz7Nxht') AS sku,
-> AES_DECRYPT(p.prod_name, 'MW4KQLg1Irfo3Xz7Nxht') AS prod_name,
-> AES_DECRYPT(p.prod_desc, 'MW4KQLg1Irfo3Xz7Nxht') AS prod_desc,
-> AES_DECRYPT(p.stock_level, 'MW4KQLg1Irfo3Xz7Nxht') AS stock_level,
-> AES_DECRYPT(p.reorder_level, 'MW4KQLg1Irfo3Xz7Nxht') AS reorder_level,
-> AES_DECRYPT(p.reorder_qty, 'MW4KQLg1Irfo3Xz7Nxht') AS reorder_qty,
-> p.vat_exempt,
-> AES_DECRYPT(p.lastorderdate, 'MW4KQLg1Irfo3Xz7Nxht') AS lastorderdate,
-> AES_DECRYPT(p.lastorderqty, 'MW4KQLg1Irfo3Xz7Nxht') AS lastorderqty,
-> AES_DECRYPT(c.category_name, 'MW4KQLg1Irfo3Xz7Nxht') AS category_name,
-> ps.sup_id
-> FROM
-> products p
-> INNER JOIN
-> product_category c
-> ON
-> p.category_id = c.category_id
-> INNER JOIN
-> product_supplier ps
-> ON
-> p.prod_id = ps.prod_id
-> INNER JOIN
-> suppliers s
-> ON
-> ps.sup_id = s.supplier_id
-> WHERE
-> AES_DECRYPT(p.prod_type, 'MW4KQLg1Irfo3Xz7Nxht') = 1
-> AND
-> AES_DECRYPT(p.stock_level, 'MW4KQLg1Irfo3Xz7Nxht') <= AES_DECRYPT(p.reorder_level, 'MW4KQLg1Irfo3Xz7Nxht')
-> AND
-> ps.preferred = 1
-> ORDER BY
-> ps.sup_id;
+---------+------+-----------------+------------------------+-------------+---------------+-------------+------------+---------------+--------------+---------------+--------+
| prod_id | sku | prod_name | prod_desc | stock_level | reorder_level | reorder_qty | vat_exempt | lastorderdate | lastorderqty | category_name | sup_id |
+---------+------+-----------------+------------------------+-------------+---------------+-------------+------------+---------------+--------------+---------------+--------+
| 7 | 7 | Term Block | Nylon connector block. | 3 | 5 | 20 | 0 | NULL | NULL | Electrical | 2 |
| 5 | 5 | Electrical Tape | Black | 12 | 20 | 100 | 0 | NULL | NULL | Electrical | 2 |
+---------+------+-----------------+------------------------+-------------+---------------+-------------+------------+---------------+--------------+---------------+--------+