join

django inner join query

I am working with django and having a hard time grasping how to do complex queries Here is my model class TankJournal(models.Model): user = models.ForeignKey(User) tank = models.ForeignKey(TankProfile) ts = models.DateTimeField(auto_now=True) title = models.CharField(max_length=50) body = models.TextField() cla...

LINQ joining two tables

I have two tables say A and B. A cols are GUID, someintVar, someMoreIntvar B col are GUID, someItemNO, SomeItemDesc Now for one GUID I will have only one row in Table A. But I can have multiple rows for the same GUID. Now I want to query the database based on GUID and select values in a class. This class will have a list that will hold ...

Ruby on Rails Join table relationship

Hello I am trying to use my join table "showing" to get a list of movies I was trying to use this code but it does not work. @showing_list = Showing.find_sorted_showings("time") @movie_list = @showing_list.movies <-- NoMethodError Here is my Showing class class Showing < ActiveRecord::Base belongs_to :movie def self.find_s...

Powershell Joins

Hi Guys, Im trying to join a number of elements of an array into a string using this; $a = "h","e","l","l","o" $b = [string]::join("", $a[0,1,2,3]) But I get a 'Missing ')' in method call' error. The join documentation only mentions joining all the elements of an array, not elements at specific indexes. Can this be done? Cheers And...

.NET Linq Join

I have 2 tables in SQL. Table 1 Step Id Step Name Table 2 Profile Id Step Id Completed I would like to return the following results even if there is not match in table 2: Results Table1.Step Id Table1.Step Name Table2.Profile Id Table2.Completed The way I am doing this in SQL is the following: select * from [Table 1] t1 left joi...

rails : what's wrong with this multiple join with conditions on the associations?

Here are my models: class Deck < ActiveRecord::Base belongs_to :game has_many :deck_cards end class DeckCard < ActiveRecord::Base belongs_to :card belongs_to :deck end class Card < ActiveRecord::Base end Here's my attempted find: DeckCard.all :joins => [:card, :deck], :conditions => {{:decks => {:game_id => @game.id}}, {:ca...

tsql : how do I join this table?

I have the following sql statement: SELECT TOP (100) PERCENT inv.CompanyID, cust.CustID AS ClientID, cust.CustName AS CustomerName, inv.InvcKey, inv.PrimarySperKey AS SperKey, inv.TranID AS InvoiceNumber, in...

Nhibernate - query with join table without relationship

Hi all: I was wondering if anyone has tried to do this in NHibernate. I have the following tables (simpify version). CITY: city (varchar2) (PK) province (varchar2) (PK) CITY_TL: city (varchar2) (PK) province (varchar2) (PK) lang (char (2)) (PK) LOCATION: location (varchar2) (PK) some other column. As you can see, there are no relat...

Left Joins are what I want but they are very slow?

Overview: I have three tables 1) subscribers, bios, and shirtsizes and i need to find the subscribers without a bio or shirtsizes the tables are laid out such as subscribers | season_id | user_id | bio | bio_id | user_id | shirt sizes | bio_id | shirtsize | And I need to find all users who do not have a bio or shirtsize, ...

SQL query - Join that returns the first two records of joining table

I have two tables: Patient pkPatientId FirstName Surname PatientStatus pkPatientStatusId fkPatientId StatusCode StartDate EndDate Patient -> PatientStatus is a one to many relationship. I am wondering if its possible in SQL to do a join which returns only the first two PatientStatus records for each Patient. If only one Patien...

Should I use the sql JOIN keyword for complex joins on multiple tables ?

I've got the following request : select * from tbA A, tbB B, tbC C, tbD D where A.ID=B.ID and B.ID2= C.ID2 and A.ID=D.ID and C.ID3=D.ID3 and B.ID4=D.ID4 and A.Foo='Foo' I've heard several times that this join syntax is depreciated, and that I should use the 'JOIN' keyword instead. How do I do that in such a complicated ...

MSSQL server and index join

Hi, I'm working on an assignment where I'm supposed to compare different join methods in SQL Server, namely hash-join, merge-join and index-join. I'm having difficulties getting SQL Server to perform an index-join. Can anyone show me how I can force it to use an index-join (using a join hint or similar), or just simply provide a simpl...

to database join or not to (move joins into application server?)

I am facing a performance (it can lead to scaling issue later on) issue at the moment. The application I am working on is quite complex and it’s running on SQL Server 2005, I need to join 6 - 7 tables to get the desired data. Each table contains more than 100,000 rows of data so far. The database schema can not be changed (must stay as i...

How to get the Join of Two One to Many associations?

I have two hibernate entities User and Blog. User can be interested in multiple Tags. Blog can belong to multiple Tags. For a User, How do i find the Blogs which belong to the Tags the User is interested in? I need something like Select * from Blog where Blog.Tags IN User.Tags except that SQL or HQL doesnt allow such comparisons in ...

What is causing this ActiveRecord::ReadOnlyRecord error?

This follows this prior question, which was answered. I actually discovered I could remove a join from that query, so now the working query is start_cards = DeckCard.find :all, :joins => [:card], :conditions => ["deck_cards.deck_id = ? and cards.start_card = ?", @game.deck.id, true] This appears to work. However, when I try to move th...

JOIN Performance: Composite key versus BigInt Primary Key

We have a table that is going to be say 100 million to a billion rows (Table name: Archive) This table will be referenced from another table, Users. We have 2 options for the primary key on the Archive table: option 1: dataID (bigint) option 2: userID + datetime (4 byte version). Schema: Users - userID (int) Archive - userID - d...

How can I make sure N threads run at roughly the same speed?

I'm toying with the idea of writing a physics simulation software in which each physical element would be simulated in its own thread. There would be several advantages to this approach. It would be conceptually very close to how the real world works. It would be much easier to scale the system to multiple machines. However, for this t...

Outer Join with some other tables in FROM

FROM [TABELA DE PRODUTOS/ESTOQUE] AS T1 , [TABELA DE PRODUTOS] AS T2 , [TABELA DE MOVIMENTAÇÃO DE ESTOQUE] AS T3 , [TABELA DE FORNECEDORES] AS T4 , [TABELA DE PRODUTOS/ESTOQUE] AS T5 WHERE (((T1.Produto)=[T2].[ID]) ETC So, how can I add a JOIN between those tables ? I need a left join, like: FROM [TABELA DE PRODUTOS/ESTOQUE] <- TABLE...

Filtering from join-table

I'm having some trouble with a tricky SQL-query. In my MySQL database there is the tables topics, tags and tags_topics to join them. I want to fetch topics that share the same specified tags. For example, let's say i have 3 tags with ids 1, 2 and 3, i want to fetch all topics that have tag 1, 2 and 3 associated to them. The topics can ...

Is the join expression not supported by MS Access?

Can anyone explain to me what is wrong with my query? SELECT T2.TIPOPRODUTO , T2.PRODUTO , T1.ESPESSURA , '' AS LARGURA , '' AS COMPRIMENTO , '' AS [ACABAM REVEST] , '' AS [ESPECIF QUALIDADE] , T1.CÓDIGORASTREABILIDADE , T3.DATA , T4.NOMEFANTASIA , T7.NOME , T5.DT_INICIO_RESERVA , T1.PESO ...