Rails控制檯不同的MySQL結果

Question

我在使用Rails的LEFT OUTER JOIN時遇到問題。我想我已經關閉了Ruby代碼，但是當我將它輸入到rails console時，我得到了一個結果，當我複製生成的MySQL時，我得到了另一個結果。 rails console中缺少整列（值）。爲什麼SQL是完全相同的，但我得到不同的結果？理想情況下，我希望結果包含值列。一如既往的幫助將不勝感激。

Rails的控制檯響應

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的迴應只有

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

從SecurityItem類的屬性出現在返回結果。但是，您可以通過'attributes'方法訪問連接表中的屬性。

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'] }