ActiveRecord的阿雷尔OR条件 [英] ActiveRecord Arel OR condition
问题描述
使用逻辑,而不是或你怎么可以将2个不同的条件是什么?
注意: 2的条件产生的轨道范围,并不能轻易变成像其中(X或Y)
直接。
简单的例子:
管理员= User.where(:一种=>:管理员)
作者= User.where(:一种=>:作者)
这是很容易申请和条件(对于这种特殊情况下是没有意义的):
(admins.merge作者).to_sql
#=>选择...从...其中一种='管理员'AND KIND =作者
但你怎么能生产出具有以下查询2不同阿雷尔关系已有的?
#=>选择...从...其中一种='管理员'或种类=作者
看来(根据阿雷尔自述):
目前尚不支持OR运算符
不过,我希望它在这里并不适用,想到写这样的:
(admins.or作者).to_sql
我有点迟到了,但这里是我能想出的最好的建议:
管理员= User.where(:一种=>:管理员)
作者= User.where(:一种=>:作者)
管理员= admins.where_values.reduce(:和)
作者= authors.where_values.reduce(:和)
User.where(admins.or(作者))。to_sql
#=> 选择\用户\。* FROM \用户\WHERE((\用户\\一种\=管理员或\用户\\一种\=作者) )
How can you combine 2 different conditions using logical OR instead of AND?
NOTE: 2 conditions are generated as rails scopes and can't be easily changed into something like where("x or y")
directly.
Simple example:
admins = User.where(:kind => :admin)
authors = User.where(:kind => :author)
It's easy to apply AND condition (which for this particular case is meaningless):
(admins.merge authors).to_sql
#=> select ... from ... where kind = 'admin' AND kind = 'author'
But how can you produce the following query having 2 different Arel relations already available?
#=> select ... from ... where kind = 'admin' OR kind = 'author'
It seems (according to Arel readme):
The OR operator is not yet supported
But I hope it doesn't apply here and expect to write something like:
(admins.or authors).to_sql
I'm a little late to the party, but here's the best suggestion I could come up with:
admins = User.where(:kind => :admin)
authors = User.where(:kind => :author)
admins = admins.where_values.reduce(:and)
authors = authors.where_values.reduce(:and)
User.where(admins.or(authors)).to_sql
# => "SELECT \"users\".* FROM \"users\" WHERE ((\"users\".\"kind\" = 'admin' OR \"users\".\"kind\" = 'author'))"
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