I have a TourDet model which has amongst others the following persisted attribs:
tdclientid
tdsuppid
tdpaxnos
tdpriceperpax
I also have the following in TourDet class
def tourval
tdpaxnos * tdpricerperpax
end
I am now trying to do the following:
tdis = TourDet.find(:all, conditions: ['tdtourhdrid = 23'], group: [:tdsuppid,:tdclientid], select: ['tdsuppid,tdclientid,sum(tourval) as ttl'])
However rails complains of Unknown column 'tourval'.
Any ideas on how I can achieve the same result in another way?
I'm using Rails 3.2 with Ruby 1.9 and MySQL.
As I understand your app, you can't refer to tourval in your query, as it's defined in the Ruby, not in MySQL.
How about this?
tdis = TourDet.find(:all, conditions: ['tdtourhdrid = 23'], group: [:tdsuppid,:tdclientid], select: ['tdsuppid,tdclientid,sum(tdpaxnos*tdpricerperpax) as ttl'])
Related
I'm trying to learn about SQL injections and have tried to implement these, but when I put this code in my controller:
params[:username] = "johndoe') OR admin = 't' --"
#user_query = User.find(:first, :conditions => "username = '#{params[:username]}'")
I get the following error:
Couldn't find all Users with 'id': (first, {:conditions=>"username = 'johndoe') OR admin = 't' --'"}) (found 0 results, but was looking for 2)
I have created a User Model with the username "johndoe", but I am still getting no proper response. BTW I am using Rails 4.
You're using an ancient Rails syntax. Don't use
find(:first, :condition => <condition>) ...
Instead use
User.where(<condtion>).first
find accepts a list of IDs to lookup records for. You're giving it an ID of :first and an ID of condition: ..., which aren't going to match any records.
User.where(attr1: value, attr2: value2)
or for single items
User.find_by(attr1: value, attr2: value)
Bear in mind that while doing all this, it would be valuable to check what the actual sql statement is by adding "to_sql" to the end of the query method (From what I remember, find_by just does a LIMIT by 1)
How in yii 1.1.7 using CDbCriteria and CActiveDataProvider to make subquery for calculaion number of rows in related table in 1 request ?
In CodeIgniter I wrote like :
$CategoryFactory = ORM::factory('category');
$CategoryFactory->select( DB::expr( ' ( select count(*) from `tour` where `tour`.`category_id` = `category`.`id` ) as related_tours_count ' ) );
...
$category_result= $CategoryFactory->find_all();
Is there is similar way in yii 1.1.7 ?
I never used codeIgniter, but in Yii must define a Model and then use countBySql method
or any other method of the CActiveRecord class
I'm new to Ruby on Rails. I'm trying to determine the proper ruby query for the following SQL query.
Select max(bid_amount) from biddings where listing_id = 1;
I need to extract the maximum value in the bid_amount column. But it has to have a dynamic listing_id.
Try:
Bidding.where('listing_id = :listing_id', listing_id: 1).maximum(:bid_amount)
Update:
To follow up on your comment: since you say you are passing in params[:id], it's best to convert that parameter to integer so that unwanted values don't go to the database. For e.g.
Bidding.where('listing_id = :listing_id', listing_id: params[:id].to_i).maximum(:bid_amount)
How do I query distinct with MongoMapper? My query is:
subscribedToThread = Comment.where(:subscribe_thread => 1).all
But this will return many objects with the same user_id. I need to return just a distinct user_id. Is this possible?
I think you will need to drop down to the ruby driver in order to do this as I don't think you can do this with MongoMapper itself:
subscribedToThread = Comment.collection.distinct("user_id", {:subscribe_thread => 1})
Calling the collection method on a model returns the collection as would be provided by the Ruby driver directly so you can issue a distinct query using the syntax below:
collection.distinct(key, query = nil)
You can read more about it here
Yes, you can do so:
subscribedToThread = Comment.where(:subscribe_thread => 1).fields(:user_id).all.compact!.unique!
This will nil every field but user_id which you then uniq!,ie you remove all doubles and then compact! all nil
http://mongomapper.com/documentation/plugins/querying.html#fields
Try this
subscribedToThread = Comment.where(:subscribe_thread => 1).fields(:user_id).collect(&:user_id).uniq
It will show you list of uniq user_id
suppose we have a model in django defined as follows:
class Literal:
name = models.CharField(...)
...
Name field is not unique, and thus can have duplicate values. I need to accomplish the following task:
Select all rows from the model that have at least one duplicate value of the name field.
I know how to do it using plain SQL (may be not the best solution):
select * from literal where name IN (
select name from literal group by name having count((name)) > 1
);
So, is it possible to select this using django ORM? Or better SQL solution?
Try:
from django.db.models import Count
Literal.objects.values('name')
.annotate(Count('id'))
.order_by()
.filter(id__count__gt=1)
This is as close as you can get with Django. The problem is that this will return a ValuesQuerySet with only name and count. However, you can then use this to construct a regular QuerySet by feeding it back into another query:
dupes = Literal.objects.values('name')
.annotate(Count('id'))
.order_by()
.filter(id__count__gt=1)
Literal.objects.filter(name__in=[item['name'] for item in dupes])
This was rejected as an edit. So here it is as a better answer
dups = (
Literal.objects.values('name')
.annotate(count=Count('id'))
.values('name')
.order_by()
.filter(count__gt=1)
)
This will return a ValuesQuerySet with all of the duplicate names. However, you can then use this to construct a regular QuerySet by feeding it back into another query. The django ORM is smart enough to combine these into a single query:
Literal.objects.filter(name__in=dups)
The extra call to .values('name') after the annotate call looks a little strange. Without this, the subquery fails. The extra values tricks the ORM into only selecting the name column for the subquery.
try using aggregation
Literal.objects.values('name').annotate(name_count=Count('name')).exclude(name_count=1)
In case you use PostgreSQL, you can do something like this:
from django.contrib.postgres.aggregates import ArrayAgg
from django.db.models import Func, Value
duplicate_ids = (Literal.objects.values('name')
.annotate(ids=ArrayAgg('id'))
.annotate(c=Func('ids', Value(1), function='array_length'))
.filter(c__gt=1)
.annotate(ids=Func('ids', function='unnest'))
.values_list('ids', flat=True))
It results in this rather simple SQL query:
SELECT unnest(ARRAY_AGG("app_literal"."id")) AS "ids"
FROM "app_literal"
GROUP BY "app_literal"."name"
HAVING array_length(ARRAY_AGG("app_literal"."id"), 1) > 1
Ok, so for some reason none of the above worked for, it always returned <MultilingualQuerySet []>. I use the following, much easier to understand but not so elegant solution:
dupes = []
uniques = []
dupes_query = MyModel.objects.values_list('field', flat=True)
for dupe in set(dupes_query):
if not dupe in uniques:
uniques.append(dupe)
else:
dupes.append(dupe)
print(set(dupes))
If you want to result only names list but not objects, you can use the following query
repeated_names = Literal.objects.values('name').annotate(Count('id')).order_by().filter(id__count__gt=1).values_list('name', flat='true')