Approval.where("user1_approval IS NOT NULL AND user2_approval IS NOT NULL AND (user_id = ? OR approved_id = ?)", user.id, user.id)
I want the part in parenthesis to work -- either of those statements. Currently I get an error on the parenthesis when I run this query.
How can I make this query?
Do you mind to use ActiveRecord query like this ?
Approval.where.not(user1_approval:nil).where.not(user2_approval: nil).where("summoner_id = ? OR approved_id = ?", user.id, user.id)
It might reduce the potential problem in writing plain SQL.
Related
I have this query:
absences = Absence.joins(:user).where('users.company_id = ?', #company.id).where('"from" <= ? and "to" >= ?', self.date, self.date).group('user_id').select('user_id, sum(hours) as hours')
This will return user_id's with a total of hours.
Now I need to to loop through all users of the company and do some calculations.
company.users.each do |user|
tc = TimeCheck.find_or_initialize_by(:user_id => user.id, :date => self.date)
tc.expected_hours = user.working_hours - absences.where('user_id = ?', user.id).first.hours
end
For performance reasons I want to have only one query to the absences table (the first one) and afterwards to look in memory for the correct user. How do I best accomplish this? I believe by default absences will be a ActiveRecord::Relation and not a result set. Is there a command I can use to instruct activerecord to execute the query, and afterwards search in memory?
Or do I need to store absences as array or hash first?
One SQL optimization you could make is:
change:
absences.where('user_id = ?', user.id).first.hours
to:
absences.detect { |u| u.user_id == user.id }.hours
Also, You might not need to loop through company.users. You may be able to loop through absences instead, depending on the business requirements.
In Ruby on Rails, I'm trying to order the matches of a player by whether the current user is the winner.
The sort order would be:
Sort by whether the current user is the winner
Then sort by created_at, etc.
I can't figure out how to do the equivalent of :
Match.all.order('winner_id == ?', #current_user.id)
I know this line is not syntactically correct but hopefully it expresses that the order must be:
1) The matches where the current user is the winner
2) the other matches
You can use a CASE expression in an SQL ORDER BY clause. However, AR doesn't believe in using placeholders in an ORDER BY so you have to do nasty things like this:
by_owner = Match.send(:sanitize_sql_array, [ 'case when winner_id = %d then 0 else 1 end', #current_user.id ])
Match.order(by_owner).order(:created_at)
That should work the same in any SQL database (assuming that your #current_user.id is an integer of course).
You can make it less unpleasant by using a class method as a scope:
class Match < ActiveRecord::Base
def self.this_person_first(id)
by_owner = sanitize_sql_array([ 'case when winner_id = %d then 0 else 1 end', id])
order(by_owner)
end
end
# and later...
Match.this_person_first(#current_user.id).order(:created_at)
to hide the nastiness.
This can be achived using Arel without writing any raw SQL!
matches = Match.arel_table
Match
.order(matches[:winner_id].eq(#current_user.id).desc)
.order(created_at: :desc)
Works for me with Postgres 12 / Rails 6.0.3 without any security warning
If you want to do sorting on the ruby side of things (instead of the SQL side), then you can use the Array#sort_by method:
query.sort_by(|a| a.winner_id == #current_user.id)
If you're dealing with bigger queries, then you should probably stick to the SQL side of things.
I would build a query and then execute it after it's built (mostly because you may not have #current_user. So, something like this:
query = Match.scoped
query = query.order("winner_id == ?", #current_user.id) if #current_user.present?
query = query.order("created_at")
#results = query.all
I have these two pieces of code that each return a relation inside the Micropost model.
scope :including_replies, lambda { |user| where("microposts.in_reply_to = ?", user.id)}
def self.from_users_followed_by(user)
followed_user_ids = user.followed_user_ids
where("user_id IN (?) OR user_id = ?", followed_user_ids, user)
end
When I run r1 = Micropost.including_replies(user) I get a relation with two results with the following SQL:
SELECT `microposts`.* FROM `microposts` WHERE (microposts.in_reply_to = 102) ORDER BY
microposts.created_at DESC
When I run r2 = Micropost.from_users_followed_by(user) I get a relation with one result with the following SQL:
SELECT `microposts`.* FROM `microposts` WHERE (user_id IN (NULL) OR user_id = 102) ORDER
BY microposts.created_at DESC
Now when I merge the relations like so r3 = r1.merge(r2) I got zero results but was expecting three. The reason for this is that the SQL looks like this:
SELECT `microposts`.* FROM `microposts` WHERE (microposts.in_reply_to = 102) AND
(user_id IN (NULL) OR user_id = 102) ORDER BY microposts.created_at DESC
Now what I need is (microposts.in_reply_to = 102) OR (user_id IN (NULL) OR user_id = 102)
I need an OR instead of an AND in the merged relation.
Is there a way to do this?
Not directly with Rails. Rails does not expose any way to merge ActiveRelation (scoped) objects with OR. The reason is that ActiveRelation may contain not only conditions (what is described in the WHERE clause), but also joins and other SQL clauses for which merging with OR is not well-defined.
You can do this either with Arel directly (which ActiveRelation is built on top of), or you can use Squeel, which exposes Arel functionality through a DSL (which may be more convenient). With Squeel, it is still relevant that ActiveRelations cannot be merged. However Squeel also provides Sifters, which represent conditions (without any other SQL clauses), which you can use. It would involve rewriting the scopes as sifters though.
Rails 2.35
I'm may be wrong but I thought with an array in a paramater, rails was suppose to comman seperate the array when used like below for a query. I know I can break the param out into a single quoted and comma seperated string. I was just curious is this can be automatically done by Rails and how I might go about it if so. Thank You
Parameters being sent:
Parameters: {"method"=>:get, "id"=>["3", "1", "4"]}
The SQL statement in the controller I'm using:
sql = "SELECT user.user_alias from users " +
"where user.id in (#{params[:id]}) " +
"AND user.user_alias is NOT NULL "
aliases = User.find_by_sql(sql)
The SQL string Rails outputs (the query results in the IN statement are just all togather '314):
SELECT User.user_alias
from lte_users
where user.id in (314)
AND user.user_alias is NOT NULL
NEVER, never, do string concatenation in a SQL query, as someone might use this to perform an SQL Injection attack on your webapp.
You should be doing it like this:
sql = %Q{SELECT user.user_alias from users
where user.id in (?)
AND user.user_alias is NOT NULL }
aliases = User.find_by_sql([ sql, params[:id] ])
Unless you desperately need the performance of not creating ActiveRecord objects for the few records returned, I'd do this idiomatically like:
aliases = User.all(
:conditions => ['id IN (?) AND user_alias IS NOT NULL', params[:id]
).map(&:user_alias)
Try:
where user.id in (#{params[:id].join(',')})
I want to have a where clause with an equal and does not equal condition:
#user = User.where(:user_id => current_user.id, :author_id != current_user.id).nil? ? (render :something) : (render :somethingelse)
The above does not work:
syntax error, unexpected ')',
expecting tASSOC ...d, :user_id !=
current_user.id).nil? ? (render
:index) : (re...
If I change the second condition from != to => it will work, however.
How do I have both conditions in one where clase? Thank you
Here's how you would use Arel to generate the query "select * from users where user_id = ? and author_id != ?":
users = User.arel_table
User.where(users[:user_id]. eq(current_user.id).and(
users[:author_id].not_eq(current_user.id)))
Using Arel isn't as concise as using Hash conditions for simple conditions, but it's a lot more powerful!
Here's a link to the full list of predications (eq, not_eq, gt, lt, etc.) available with Arel.
I believe, it should be:
#user = User.where(['user_id = ? AND author_id <> ?', current_user.id, current_user.id])
render(#user ? :something : :somethingelse)
Rails 4 has this all figured out
Model.where.not(:colname => nil)
#=> returns all records whose :colname values are not nil
The syntax error is due to you attempting to use != instead of =>. The where method does not support inequality with hashed arguments, so your not equal will need to be written using array arguments.
User.where(:user_id => current_user.id).where(['users.author_id <> ?', current_user.id])
http://guides.rubyonrails.org/active_record_querying.html#hash-conditions
Only equality, range and subset checking are possible with Hash conditions.
You'll need to either drop down to straight SQL or invert and arel query, see Is there a way to invert an ActiveRecord::Relation query?
Not sure if you're aware, the not equal condition typically does not match (author_id) NULL values. You'll have to do an OR author_id IS NULL if you want that.
#users = User.where("user_id = ? AND (author_id != ? OR author_id IS NULL)",
current_user.id, current_user.id)
render(#users.present? ? :something : :somethingelse)
Also note that I'm using #users.present? because where finder returns an ActiveRecord::Relation array.