从具有不同键值的mysql中选择

Question

我想写一些查询，它给我带有特定键值的产品

tbl_product

  product_id  field_id    value
      1          1         100
      1          2         200

我想找到所有产品（field_id = 1和value = 100）和（field_id = 2且值= 200）

Answer 1

您可以使用where，group by和having：

select product_id
from t
where (field_id = 1 and value = 100) or (field_id = 2 and value = 200 )
group by product_id
having count(*) = 2;

如果允许重复，则需要count(distinct field_id) = 2。

Answer 2

我想你似乎想要：

select t.*
from table t
where exists (select 1 
              from table 
              where product_id = t.product_id and (field_id = 1 and value = 100)  
             ) and
      exists (select 1 
              from table 
              where product_id = t.product_id and (field_id = 2 and value = 200)  
             );