Question

我正在尝试比较两个不同制造商之间的产品表中的product_models。我发现同一产品有2个不同的product_model号码。相似但仍然不同。例如，制造商1（ELD）的CNELD-1004与制造商2（MC）的1004相同。我试图展示制造商2的产品，它不像制造商1的相同product_model

不使用php，有没有办法做这个mysql？

select products_model  AS MCProducts from products where manufacturers_id = 2; 

select products_model  AS ELDProducts from products where manufacturers_id = 1; 

Select  MCProducts from products WHERE MCProducts  not LIKE  "%ELDProducts%"

Answer 1

选择products_model，CASE

  WHEN manufacturers_id = 2 THEN 'MCProducts' 
  WHEN manufacturers_id = 2 THEN 'ELDProducts'
  END 
from products where WHERE MCProducts  not LIKE  "%ELDProducts%"

Answer 2

我想这也行。

select products_model  AS MCProducts from products where manufacturers_id = 2 and     products_model not in (select products_model  from products where manufacturers_id = 1);

如何比较WHERE子句定义的同一个表中的字段

2 个答案: