Rails控制台不同的MySQL结果

Question

我在使用Rails的LEFT OUTER JOIN时遇到问题。我想我已经关闭了Ruby代码，但是当我将它输入到rails console时，我得到了一个结果，当我复制生成的MySQL时，我得到了另一个结果。 rails console中缺少整列（值）。为什么SQL是完全相同的，但我得到不同的结果？理想情况下，我希望结果包含值列。一如既往的帮助将不胜感激。

Rails的控制台响应

2.0.0-p353 :023 > SecurityItem.joins("LEFT OUTER JOIN security_role_permissions ON security_role_permissions.security_item_id = security_items.id AND security_role_permissions.role_id ='1'").select("security_items.name, security_role_permissions.value") 

SecurityItem Load (0.7ms) SELECT security_items.name, security_role_permissions.value FROM `security_items` LEFT OUTER JOIN security_role_permissions ON security_role_permissions.security_item_id = security_items.id AND security_role_permissions.role_id ='1 

=> #<ActiveRecord::Relation 
[#<SecurityItem id: nil, key: "ChangePassword", name: "Change Password">, 
#<SecurityItem id: nil, key: "AddUsers", name: "Add Users">, 
#<SecurityItem id: nil, key: "UpdateUsers", name: "Update Users">, 
#<SecurityItem id: nil, key: "DeleteUsers", name: "Delete Users">]> 

MySQL的回应只有

mysql> SELECT security_items.name, security_role_permissions.value FROM `security_items` LEFT OUTER JOIN security_role_permissions ON security_role_permissions.security_item_id = security_items.id AND security_role_permissions.role_id ='1'; 

+-----------------+-------+ 
| name   | value | 
+-----------------+-------+ 
| Change Password |  1 | 
| Add Users  | NULL | 
| Update Users | NULL | 
| Delete Users | NULL | 
+-----------------+-------+ 

Answer 1

从SecurityItem类的属性出现在返回结果。但是，您可以通过'attributes'方法访问连接表中的属性。

security_items = SecurityItem.joins("LEFT OUTER JOIN security_role_permissions 
ON security_role_permissions.key = security_items.key AND 
security_role_permissions.role_id ='1'").select("security_items.name, 
security_items.key, security_role_permissions.permission") 

security_items.each { |security_item| puts security_item.attributes['permission'] }