Ruby-on-rails activerecord 查找所有未包含在数组中的内容
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activerecord find all NOT included in an array
提问by kjs3
I have an array of team names from another part of code and I want to find all the Teams not in that array. I've tried the following and it doesn't work.
我有一组来自另一部分代码的团队名称，我想找到不在该数组中的所有团队。我已经尝试了以下方法，但它不起作用。
@team_exclude_list = ['Team 1', 'Team 2', 'Team 3']
@teams = Team.where("name != ?", @team_exclude_list)
This is in Rails 3 and the Googles aren't giving me much love.
这是在 Rails 3 中，谷歌并没有给我太多的爱。
回答by nslocum
Rails 4 solution:
Rails 4 解决方案：
@team_exclude_list = ['Team 1', 'Team 2', 'Team 3']
@teams = Team.where.not(name: @team_exclude_list)
Also, to speed up the query, you can:
此外，为了加快查询速度，您可以：
- create an index on name
- 在名称上创建索引
OR
或者
- change the query to use IDs which are indexed by default
- 更改查询以使用默认索引的 ID
回答by Stéphan Kochen
I've never done this with a string field, but perhaps this will work:
我从来没有用字符串字段做过这个，但也许这会奏效：
@teams = Team.where("name NOT IN (?)", @team_exclude_list)
