When using a SQL join, is it possible to keep only rows that have a single row for the left table? For example: select * from A, B where A.id = B.a_id; a1 b1 a2 b1 a2 b2 In this case, I want to remove all except the first row, where a single row from A matched exactly 1 row from B. I'm using MySQL. ...
Hello Everybody I am thinking 5-6 hours to understand something about GroupJoin. I am talking about query with linq for Database tables.I understand what Join and GroupJoin does but I really couldn't understand where i will need it.I feel that Join does all what i will need but if there is something which Join can't without GroupJoin so...
its Access database.. i have a Library table, where Autnm Topic Size Cover Lang are foreign Keys each record is actually a book which has its properties such as author and stuff. i am not quite sure i am even using the correct JOIN.. quite new with "complex" SQL :) SELECT Library.Bknm_Hebrew, Library.Bknm_English, Library.Bknm_Russia...
I have 2 tables: book ( id, title, age ) ----> 100 milions of rows author ( id, book_id, name, born ) ----> 10 millions of rows Now, supposing I have a generic id of a book. I need to print this page: Title: mybook authors: Tom, Graham, Luis, Clarke, George So... what is the best way to do this ? 1) Simple join like this: Select...
if i have queries on multiple tables like: d = Relations.objects.filter(follow = request.user).filter(date_follow__lt = last_checked) r = Reply.objects.filter(reply_to = request.user).filter(date_reply__lt = last_checked) article = New.objects.filter(created_by = request.user) vote = Vote.objects.filter(voted = article).filter(date__lt ...
I am curious on how exactly LINQ (not LINQ to SQL) is performing is joins behind the scenes in relation to how Sql Server performs joins. Sql Server before executing a query, generates an Execution Plan. The Execution Plan is basically an Expression Tree on what it believes is the best way to execute the query. Each node provides inform...
At the moment I can get the results I need with two seperate SELECT statements SELECT COUNT(rl.refBiblioID) FROM biblioList bl LEFT JOIN refList rl ON bl.biblioID = rl.biblioID GROUP BY bl.biblioID SELECT GROUP_CONCAT( CONCAT_WS( ':', al.lastName, al.firstName ) ORDER BY al.authorID ) FROM biblioList bl LEFT JOIN biblio_author b...
He guys, I'm stuck with a problem and I hope someone can help me out. I have a date. For example 2009-10-1. This date is used to check in which season I am working. This could be summer or winter. If whe are in the summer the table to use for my inner join whould be 'summer09_rooms'. If winter 'winter09_rooms'. So I basicly whant to do ...
Hi, i have 2 table (user, user_profile) without a explicit relationship in the sql db. and i can't add it to the db. so, i can't do this: db.user.include("user_profile") the attribute in for the join is user_id is possible do anything like this? db.user.join("user_profile On user.id = user_profile.user_id") How can i do that? th...
My scenario: There are 3 tables for storing tv show information; season, episode and episode_translation. My data: There are 3 seasons, with 3 episodes each one, but there is only translation for one episode. My objetive: I want to get a list of all the seasons and episodes for a show. If there is a translation available in a specified...
Possible Duplicate: Flatten (an irregular) list of lists in Python Hay All. I have a list which consists of many lists, here is an example [ [Obj, Obj, Obj, Obj], [Obj], [Obj], [ [Obj,Obj], [Obj,Obj,Obj] ] ] Is there a way to join all these items together as 1 list, so the output will be...
Hi, I'm not much of a SQL man so I'm seeking help for this one. I have a site where I have a database for all accounts and whatnot, and another for storing actions that the user has done on the site. Each user has their own table but I want to combine the data of each user group ( all users that are "linked together" ) and order that da...
Is it possible to make a join in SQL server that joins each row from table A to n random rows in another? For example, say I have a Customer table, a Product table and an Order table. I want to join each customer to 5 random products and insert these rows into the order table. (And each customer should be joined to 5 random rows of his o...
I have a model Painting which has a Paintingtitle in each language and a Paintingdescription in each language: class Painting < ActiveRecord::Base has_many :paintingtitles, :dependent => :destroy has_many :paintingdescriptions, :dependent => :destroy end class Paintingtitle < ActiveRecord::Base belongs_to :painting belongs_to...
On the project I am working on, I am stuck with the table structure from Hades. Two things to keep in mind: I can't change the table structure right now. I'm stuck with it for the time being. The queries are dynamically generated and not hard coded. So, while I am asking for a query that can pull this data, what I am really working t...
I have a mysql database with movies as follows: MOVIES(id,title) KEYWORDS_TABLE(id,key_id) [id is referenced to movies.id, key_id is refernced to keywords.id] KEYWORDS(id,keyword) //this doesn't matter on my example.. Basically i have movies with their titles and plot keywords for each one, i want to select all movies...
i have a mini blog app, and a 'timeline' . there i want to be displayed all the posts from all the friends of a user, plus the posts of that user himself. For that, i have to make some kind of a 'join' between the results of two queries (queries on the same table) , so that the final result will be the combination of the user - posesor o...
There are three tables in my db ITEM_MASTER, PRICE_MASTER, COMP_MASTER ITEM_MASTER STORE_CODE ITEM_CODE ITEM_DESC 011 914004 desccc PRICE_MASTER STORE_CODE ITEM_CODE COMP_CODE 011 914004 01 011 914004 02 011 914004 03 011 914004 04 COMP_MASTER COMP_CODE CO...
Hello, I am trying to figure out the SQL for doing some relatively simple operations on sets of records in a table but I am stuck. Consider a table with multiple rows per item, all identified by a common key. For example: serial model color XX1 A blue XX2 A blue XX3 A green XX5 B red XX6 B blue XX1 B ...
I've got three tables; Auctions, Auction Bids and Users. The table structure looks something like this: Auctions: id title -- ----- 1 Auction 1 2 Auction 2 Auction Bids: id user_id auction_id bid_amt -- ------- ---------- ------- 1 1 1 200.00 2 2 1...