Mysql在同一查询中使用多个不同的where条件进行多次选择

我有下表：

+--------------------+-----------+--------------------+
| Product            | website   | is_master          |
+--------------------+-----------+--------------------+
| product A          |       X   | 1                  |
| product A          |       Y   | 0                  |
| product A          |       Z   | 0                  |
| product A          |       C   | 0                  |
| product B          |       D   | 1                  |
| product C          |       E   | 1                  |
+--------------------+-----------+--------------------+

我正在尝试进行mysql查询，以获得如下表a：

+--------------------+------------------+--------------------+
| Product            | master_website   | additional_sites   |
+--------------------+------------------+--------------------+
| product A          |       X          | y,z,c              |
| product B          |       D          | null               |
| product C          |       E          | null               |
+--------------------+------------------+--------------------+

我尝试过使用subselect查询，但在这两种情况下都失败了

select 
Product, 
    (select Product 
     FROM `table1` 
     LEFT JOIN 
     table2 on table1.id = table2.fk_table1 
     WHERE is_master = 1) is_master, 

    (select group_concat(Product) 
     FROM `table1` 
     LEFT JOIN 
     table2 on table1.id = table2.fk_table1 
     WHERE is_master = 0) additional 

     FROM `table1` 
     LEFT JOIN 
     table2 on table1.id = table2.fk_table1 

WHERE 1 
group by 
Product 

问题是subselect返回多行

---

您可以在2个子选择1中断开联接查询，以便为每个产品仅选择一条记录，其中，is_master=1，我假设每个产品只有一行is_master=1，第二个子选择将选择其中，is_master=0的行，然后使用左联接进行子选择

SELECT t.*,t1.additional FROM 
(SELECT 
Product,
website AS is_master, 
FROM `table1` 
LEFT JOIN 
table2 ON table1.id = table2.fk_table1 
WHERE is_master = 1 
) t
LEFT JOIN 
(
  SELECT Product ,GROUP_CONCAT(website) additional
  FROM `table1` 
  LEFT JOIN table2 ON table1.id = table2.fk_table1 
  WHERE is_master = 0 
  GROUP BY Product
) t1 ON(t.Product = t1.Product)

---

我已经为站点为K的产品a添加了另一行，并且主控0为您的查询提供了错误的结果，它将K显示为主控website@uesr58967我更新了我的答案。这对你更有效吗？是的，现在看起来还可以：）通过这种“自我加入”技术，你为我打开了一个全新的世界！！谢谢，很好用！

SELECT t.*,t1.additional FROM 
(SELECT 
Product,
website AS is_master, 
FROM `table1` 
LEFT JOIN 
table2 ON table1.id = table2.fk_table1 
WHERE is_master = 1 
) t
LEFT JOIN 
(
  SELECT Product ,GROUP_CONCAT(website) additional
  FROM `table1` 
  LEFT JOIN table2 ON table1.id = table2.fk_table1 
  WHERE is_master = 0 
  GROUP BY Product
) t1 ON(t.Product = t1.Product)