如何在mysql中编写这个自连接查询

Question

您好，我有一个像这样的表结构

products_id | model_num | master_model_num
   1        |  cth001   |    0 
   2        |  cth002   |    0
   3        |  cth003   |    cth001
   4        |  cth004   |    cth001
   5        |  cth005   |    0
   6        |  cth006   |    cth002

我的问题

我会在表格中提供products_id，它会让所有产品ID master_model_num等于给定model_num的{​​{1}}

我尝试了以下查询，但它没有生成我想要的结果

products_id

Answer 1

SELECT pp.products_id
    FROM products p
        INNER JOIN products pp
            ON p.model_num = pp.master_model_num
    WHERE p.products_id = '1'

Answer 2

岂不

SELECT products_id
FROM products
WHERE master_model_num = (SELECT model_num 
                          FROM products 
                          WHERE products_id = 1)

在这种情况下更有意义吗？通过在查询结尾处AND p.products_id='1'，您可以保证只会获得一条记录。

Answer 3

试试这个

SELECT 
  p.products_id 
 FROM 
   products p 
 INNER JOIN 
   products pp 
 ON 
   pp.products_master_model = p.products_model

Answer 4

SELECT p.products_id FROM products p,products pp where p.model_num=pp.master_model_num and p.products_id='1'