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When using array or string conditions inside Rails query, for example:
Scope in Location model:
scope :name_like, ->(keyword) {where("name ilike ?", keyword)}
It will have problem when using it with join table who also has column name. It is like:
Location.joins(:users).name_like('main')
It will report ambiguous column name conflicts at name.
How should I address this issue, thanks!
Change your name_like scope to use explicit name of locations. I suggest to change it as below:
scope :name_like, -> (keyword) { where("locations.name ilike ?", keyword) }
You need to use like this
scope :by_name, -> { joins(:users).where("users.name like '%?%'",'FirstName' ) }
Refer this link below.
https://apidock.com/rails/ActiveRecord/NamedScope/ClassMethods/scope
I found this scope on a blog post...
scope :search_by_title, -> (title) { where("(title like ?) OR title in (?)", "%#{title}%", title.split) }
... and I'm trying to figure out the second half of the OR pair.
If the query was "banana cake",
it seems to me like the scope would work like this
scope :search_by_title, -> ("banana cake") { where("(title like ?) OR title in (?)", "%banana cake%", ["banana","cake"]) }
and this doesn't seem useful at all.
Anyone got an example that demonstrates how this scope would work?
Thanks
The first part of the scope (before OR) will work when your title includes "banana cake".
The second part of the scope (after OR) will work when your query is either "banana" or "cake".
So, it is useful because you can search for either "banana cake" or "banana" or "cake".
If you don't have that title.split part in there, then your search for either "banana" or "cake" would not work. It will only for "banana cake".
I'm hoping there is a easy solution that doesn't involve find_by_sql, if not then I guess that will have to work.
I found this article which references this:
Topic.find(:all, :conditions => { :forum_id => #forums.map(&:id) })
which is the same as
SELECT * FROM topics WHERE forum_id IN (<#forum ids>)
I am wondering if there is a way to do NOT IN with that, like:
SELECT * FROM topics WHERE forum_id NOT IN (<#forum ids>)
Rails 4+:
Article.where.not(title: ['Rails 3', 'Rails 5'])
Rails 3:
Topic.where('id NOT IN (?)', Array.wrap(actions))
Where actions is an array with: [1,2,3,4,5]
FYI, In Rails 4, you can use not syntax:
Article.where.not(title: ['Rails 3', 'Rails 5'])
Using Arel:
topics=Topic.arel_table
Topic.where(topics[:forum_id].not_in(#forum_ids))
or, if preferred:
topics=Topic.arel_table
Topic.where(topics[:forum_id].in(#forum_ids).not)
and since rails 4 on:
topics=Topic.arel_table
Topic.where.not(topics[:forum_id].in(#forum_ids))
Please notice that eventually you do not want the forum_ids to be the ids list, but rather a subquery, if so then you should do something like this before getting the topics:
#forum_ids = Forum.where(/*whatever conditions are desirable*/).select(:id)
in this way you get everything in a single query: something like:
select * from topic
where forum_id in (select id
from forum
where /*whatever conditions are desirable*/)
Also notice that eventually you do not want to do this, but rather a join - what might be more efficient.
You can try something like:
Topic.find(:all, :conditions => ['forum_id not in (?)', #forums.map(&:id)])
You might need to do #forums.map(&:id).join(','). I can't remember if Rails will the argument into a CSV list if it is enumerable.
You could also do this:
# in topic.rb
named_scope :not_in_forums, lambda { |forums| { :conditions => ['forum_id not in (?)', forums.select(&:id).join(',')] }
# in your controller
Topic.not_in_forums(#forums)
To expand on #Trung Lê answer, in Rails 4 you can do the following:
Topic.where.not(forum_id:#forums.map(&:id))
And you could take it a step further.
If you need to first filter for only published Topics and then filter out the ids you don't want, you could do this:
Topic.where(published:true).where.not(forum_id:#forums.map(&:id))
Rails 4 makes it so much easier!
The accepted solution fails if #forums is empty. To workaround this I had to do
Topic.find(:all, :conditions => ['forum_id not in (?)', (#forums.empty? ? '' : #forums.map(&:id))])
Or, if using Rails 3+:
Topic.where( 'forum_id not in (?)', (#forums.empty? ? '' : #forums.map(&:id)) ).all
Most of the answers above should suffice you but if you are doing a lot more of such predicate and complex combinations check out Squeel. You will be able to doing something like:
Topic.where{{forum_id.not_in => #forums.map(&:id)}}
Topic.where{forum_id.not_in #forums.map(&:id)}
Topic.where{forum_id << #forums.map(&:id)}
You may want to have a look at the meta_where plugin by Ernie Miller. Your SQL statement:
SELECT * FROM topics WHERE forum_id NOT IN (<#forum ids>)
...could be expressed like this:
Topic.where(:forum_id.nin => #forum_ids)
Ryan Bates of Railscasts created a nice screencast explaining MetaWhere.
Not sure if this is what you're looking for but to my eyes it certainly looks better than an embedded SQL query.
The original post specifically mentions using numeric IDs, but I came here looking for the syntax for doing a NOT IN with an array of strings.
ActiveRecord will handle that nicely for you too:
Thing.where(['state NOT IN (?)', %w{state1 state2}])
Can these forum ids be worked out in a pragmatic way? e.g. can you find these forums somehow - if that is the case you should do something like
Topic.all(:joins => "left join forums on (forums.id = topics.forum_id and some_condition)", :conditions => "forums.id is null")
Which would be more efficient than doing an SQL not in
This way optimizes for readability, but it's not as efficient in terms of database queries:
# Retrieve all topics, then use array subtraction to
# find the ones not in our list
Topic.all - #forums.map(&:id)
You can use sql in your conditions:
Topic.find(:all, :conditions => [ "forum_id NOT IN (?)", #forums.map(&:id)])
Piggybacking off of jonnii:
Topic.find(:all, :conditions => ['forum_id not in (?)', #forums.pluck(:id)])
using pluck rather than mapping over the elements
found via railsconf 2012 10 things you did not know rails could do
When you query a blank array add "<< 0" to the array in the where block so it doesn't return "NULL" and break the query.
Topic.where('id not in (?)',actions << 0)
If actions could be an empty or blank array.
Here is a more complex "not in" query, using a subquery in rails 4 using squeel. Of course very slow compared to the equivalent sql, but hey, it works.
scope :translations_not_in_english, ->(calmapp_version_id, language_iso_code){
join_to_cavs_tls_arr(calmapp_version_id).
joins_to_tl_arr.
where{ tl1.iso_code == 'en' }.
where{ cavtl1.calmapp_version_id == my{calmapp_version_id}}.
where{ dot_key_code << (Translation.
join_to_cavs_tls_arr(calmapp_version_id).
joins_to_tl_arr.
where{ tl1.iso_code == my{language_iso_code} }.
select{ "dot_key_code" }.all)}
}
The first 2 methods in the scope are other scopes which declare the aliases cavtl1 and tl1. << is the not in operator in squeel.
Hope this helps someone.
If someone want to use two or more conditions, you can do that:
your_array = [1,2,3,4]
your_string = "SOMETHING"
YourModel.where('variable1 NOT IN (?) AND variable2=(?)',Array.wrap(your_array),your_string)
I am struggling with the best way to meta program a dynamic method, where I'll be limiting results based on conditions... so for example:
class Timeslip < ActiveRecord::Base
def self.by_car_trans(car, trans)
joins(:car)
.where("cars.trans IN (?) and cars.year IN (?) and cars.model ILIKE ?", trans, 1993..2002, car)
.order('et1320')
end
end
Let's say instead of passing in my arguments, i pass in an array of conditions with key being the fieldname, and value being the field value. so for example, I'd do something like this:
i'd pass in [["field", "value", "operator"],["field", "value", "operator"]]
def self.using_conditions(conditions)
joins(:car)
conditions.each do |key, value|
where("cars.#{key} #{operator} ?", value)
end
end
However, that doesn't work, and it's not very flexible... I was hoping to be able to detect if the value is an array, and use IN () rather than =, and maybe be able to use ILIKE for case insensitive conditions as well...
Any advice is appreciated. My main goal here is to have a "lists" model, where a user can build their conditions dynamically, and then save that list for future use. This list would filter the timeslips model based on the associated cars table... Maybe there is an easier way to go about this?
First of all, you might find an interest in the Squeel gem.
Other than that, use arel_table for IN or LIKE predicates :
joins( :car ).where( Car.arel_table[key].in values )
joins( :car ).where( Car.arel_table[key].matches value )
you can detect the type of value to select an adequate predicate (not nice OO, but still):
column = Car.arel_table[key]
predicate = value.respond_to?( :to_str ) ? :in : :matches # or any logic you want
joins( :car ).where( column.send predicate, value )
you can chain as many as those as you want:
conditions.each do |(key, value, predicate)|
scope = scope.where( Car.arel_table[key].send predicate, value )
end
return scope
So, you want dynamic queries that end-users can specify at run-time (and can be stored & retrieved for later use)?
I think you're on the right track. The only detail is how you model and store your criteria. I don't see why the following won't work:
def self.using_conditions(conditions)
joins(:car)
crit = conditions.each_with_object({}) {|(field, op, value), m|
m["#{field} #{op} ?"] = value
}
where crit.keys.join(' AND '), *crit.values
end
CAVEAT The above code as is is insecure and prone to SQL injection.
Also, there's no easy way to specify AND vs OR conditions. Finally, the simple "#{field} #{op} ?", value for the most part only works for numeric fields and binary operators.
But this illustrates that the approach can work, just with a lot of room for improvement.
I'm hoping there is a easy solution that doesn't involve find_by_sql, if not then I guess that will have to work.
I found this article which references this:
Topic.find(:all, :conditions => { :forum_id => #forums.map(&:id) })
which is the same as
SELECT * FROM topics WHERE forum_id IN (<#forum ids>)
I am wondering if there is a way to do NOT IN with that, like:
SELECT * FROM topics WHERE forum_id NOT IN (<#forum ids>)
Rails 4+:
Article.where.not(title: ['Rails 3', 'Rails 5'])
Rails 3:
Topic.where('id NOT IN (?)', Array.wrap(actions))
Where actions is an array with: [1,2,3,4,5]
FYI, In Rails 4, you can use not syntax:
Article.where.not(title: ['Rails 3', 'Rails 5'])
Using Arel:
topics=Topic.arel_table
Topic.where(topics[:forum_id].not_in(#forum_ids))
or, if preferred:
topics=Topic.arel_table
Topic.where(topics[:forum_id].in(#forum_ids).not)
and since rails 4 on:
topics=Topic.arel_table
Topic.where.not(topics[:forum_id].in(#forum_ids))
Please notice that eventually you do not want the forum_ids to be the ids list, but rather a subquery, if so then you should do something like this before getting the topics:
#forum_ids = Forum.where(/*whatever conditions are desirable*/).select(:id)
in this way you get everything in a single query: something like:
select * from topic
where forum_id in (select id
from forum
where /*whatever conditions are desirable*/)
Also notice that eventually you do not want to do this, but rather a join - what might be more efficient.
You can try something like:
Topic.find(:all, :conditions => ['forum_id not in (?)', #forums.map(&:id)])
You might need to do #forums.map(&:id).join(','). I can't remember if Rails will the argument into a CSV list if it is enumerable.
You could also do this:
# in topic.rb
named_scope :not_in_forums, lambda { |forums| { :conditions => ['forum_id not in (?)', forums.select(&:id).join(',')] }
# in your controller
Topic.not_in_forums(#forums)
To expand on #Trung Lê answer, in Rails 4 you can do the following:
Topic.where.not(forum_id:#forums.map(&:id))
And you could take it a step further.
If you need to first filter for only published Topics and then filter out the ids you don't want, you could do this:
Topic.where(published:true).where.not(forum_id:#forums.map(&:id))
Rails 4 makes it so much easier!
The accepted solution fails if #forums is empty. To workaround this I had to do
Topic.find(:all, :conditions => ['forum_id not in (?)', (#forums.empty? ? '' : #forums.map(&:id))])
Or, if using Rails 3+:
Topic.where( 'forum_id not in (?)', (#forums.empty? ? '' : #forums.map(&:id)) ).all
Most of the answers above should suffice you but if you are doing a lot more of such predicate and complex combinations check out Squeel. You will be able to doing something like:
Topic.where{{forum_id.not_in => #forums.map(&:id)}}
Topic.where{forum_id.not_in #forums.map(&:id)}
Topic.where{forum_id << #forums.map(&:id)}
You may want to have a look at the meta_where plugin by Ernie Miller. Your SQL statement:
SELECT * FROM topics WHERE forum_id NOT IN (<#forum ids>)
...could be expressed like this:
Topic.where(:forum_id.nin => #forum_ids)
Ryan Bates of Railscasts created a nice screencast explaining MetaWhere.
Not sure if this is what you're looking for but to my eyes it certainly looks better than an embedded SQL query.
The original post specifically mentions using numeric IDs, but I came here looking for the syntax for doing a NOT IN with an array of strings.
ActiveRecord will handle that nicely for you too:
Thing.where(['state NOT IN (?)', %w{state1 state2}])
Can these forum ids be worked out in a pragmatic way? e.g. can you find these forums somehow - if that is the case you should do something like
Topic.all(:joins => "left join forums on (forums.id = topics.forum_id and some_condition)", :conditions => "forums.id is null")
Which would be more efficient than doing an SQL not in
This way optimizes for readability, but it's not as efficient in terms of database queries:
# Retrieve all topics, then use array subtraction to
# find the ones not in our list
Topic.all - #forums.map(&:id)
You can use sql in your conditions:
Topic.find(:all, :conditions => [ "forum_id NOT IN (?)", #forums.map(&:id)])
Piggybacking off of jonnii:
Topic.find(:all, :conditions => ['forum_id not in (?)', #forums.pluck(:id)])
using pluck rather than mapping over the elements
found via railsconf 2012 10 things you did not know rails could do
When you query a blank array add "<< 0" to the array in the where block so it doesn't return "NULL" and break the query.
Topic.where('id not in (?)',actions << 0)
If actions could be an empty or blank array.
Here is a more complex "not in" query, using a subquery in rails 4 using squeel. Of course very slow compared to the equivalent sql, but hey, it works.
scope :translations_not_in_english, ->(calmapp_version_id, language_iso_code){
join_to_cavs_tls_arr(calmapp_version_id).
joins_to_tl_arr.
where{ tl1.iso_code == 'en' }.
where{ cavtl1.calmapp_version_id == my{calmapp_version_id}}.
where{ dot_key_code << (Translation.
join_to_cavs_tls_arr(calmapp_version_id).
joins_to_tl_arr.
where{ tl1.iso_code == my{language_iso_code} }.
select{ "dot_key_code" }.all)}
}
The first 2 methods in the scope are other scopes which declare the aliases cavtl1 and tl1. << is the not in operator in squeel.
Hope this helps someone.
If someone want to use two or more conditions, you can do that:
your_array = [1,2,3,4]
your_string = "SOMETHING"
YourModel.where('variable1 NOT IN (?) AND variable2=(?)',Array.wrap(your_array),your_string)