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• mysql query to get unique value from one column

  - by vesselyp

  i have a table named locations of which i want to select and get values in such a way that it should select only distinct values from a column but select all other values . table name: locations column names 1: country values : America, India, India, India column names 2: state/Province : Newyork, Punjab, Karnataka, kerala when i select i should get India only once and all the three states listed under India . is ther any way..??? sombody please help

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• Consecutive absences in MySQL

  - by pepersview

  Hi, I have 2 tables in my db: students and absences. In students: id_student, s_name; and in absences: id_student, date, day(the day of the week as number-it's not so important); I would like to get the students that were absent for more than 2 days consecutive and the dates. At the moment I have the next query: /*To control when the days are in the same week*/ SELECT id_student, date, dayname(date),date_add(date, INTERVAL 1 DAY) AS a, dayname(date_add(date, INTERVAL 1 DAY)) AS an, date_add(date, INTERVAL 2 DAY) AS b, dayname(date_add(date, INTERVAL 2 DAY)) AS bn FROM absences AS a WHERE id_student IN (SELECT id_student FROM absences WHERE id_student = a.id_student AND date = date_add(a.date, INTERVAL 1 DAY) ) AND id_student IN (SELECT id_student FROM absences WHERE id_student = a.id_student AND date = date_add(a.date,INTERVAL 2 DAY) ) UNION /*To control when the days jump to the next week*/ SELECT id_student, date, dayname(date),date_add(date, INTERVAL 3 DAY) AS a, dayname(date_add(date, INTERVAL 3 DAY)) AS an, date_add(date, INTERVAL 4 DAY) AS b, dayname(date_add(date, INTERVAL 4 DAY)) AS bn FROM absences AS a WHERE id_student IN (SELECT id_student FROM absences WHERE id_student = a.id_student AND date = date_add(a.date, INTERVAL 3 DAY) ) AND id_student IN (SELECT id_student FROM absences WHERE id_student = a.id_student AND date = date_add(a.date,INTERVAL 4 DAY) ) /* To avoid the case (Monday-Thursday-Friday) to be consider as consecutive days*/ AND WEEKDAY(date) !=0 Thanks

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• Trying to get unique records with MySQL

  - by Joshmattvander

  I have a query that is looking at a 'page_views' table. And I so far have the ability to get the total views by day. However, I am having an issue with getting unique views by day. The column I am testing against is user_id... Here's the query I have for total views. SELECT site_id, CONCAT(month(created_at) , '-', day(created_at), '-' , year(created_at)) as created_at_date, COUNT(*) as total_results FROM page_views GROUP BY day(created_at) I can't figure out the logic to just get the unique views, by day based on the user_id column though.

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• Mysql - GROUP BY Avoid using tempoary

  - by jwzk

  The goal of this query is to get a total of unique records (by IP) per ref ID. SELECT COUNT(DISTINCT ip), GROUP_CONCAT(ref.id) FROM `sess` sess JOIN `ref` USING(row_id) WHERE sess.time BETWEEN '2010-04-21 00:00:00' AND '2010-04-21 23:59:59' GROUP BY ref.id ORDER BY sess.time DESC The query works fine, but its using a temporary table. Any ideas?

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• Updating an integer defined column in a MySQL DB with PHP

  - by Zloy Smiertniy

  I have a table defined like this: create table users ( id int(10), age int(3), name varchar (50) ) I want to use a query to update just age, which is an integer, that comes from an html form. When it arrives to the method that updates it, it comes as a string, so I change it to integer with PHP and try to update the table, but it doesn't work $age = intval($age); $q2 = "UPDATE users SET age='$age' where username like '$username';"; mysql_query($q2,$con);

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• Select in MySQL based on two tables

  - by Deyan

  Hello everyone, first of all I want to apologize for my bad english. So I have two tables. diseases ----------------------------- | ID | NAME | ----------------------------- | 1 | Disease 1 | | 2 | Disease 2 | | 3 | Disease 3 | diseases_symptoms ----------------------------- | DISEASE_ID | SYMPTOM_ID | ----------------------------- | 1 | 1 | | 1 | 2 | | 1 | 3 | | 1 | 4 | | 2 | 1 | | 2 | 2 | I want to select all diseses which have symptoms 1 or 2 and 3 or 4. I've tried: SELECT * FROM diseases_symtoms WHERE (symptoms = '1' OR symptoms = '2') AND (symptoms = '3' OR symptoms = '4') And: SELECT * FROM diseases_symtoms WHERE symptoms IN ('1','2') AND symptoms IN ('3','4') but it is not working.

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• MySql mutliple tables

  - by Chris Harrison

  I've been looking into JOIN, subqueries and other ways of doing this, but I can't work out the best way to do this is... I have a table (ps_category_product): id_product, id_category I want to perform a query on it like: SELECT id_product FROM ps_category_product WHERE id_category='$this_cat' BUT, I only want to perform this query where the ID's are returned by a query on another table (ps_product): id_product, active SELECT id_product FROM ps_product WHERE active='1' Can anyone help me with getting these two queries working together?

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• rake db:create not working for legacy rails app (2.3.5) using MySQL (5.5.28)

  - by ridicter

  I'm a new Rails Developer, and I'm working on a legacy Rails app. Whenever I run the rake db:create command, I get an error that the database couldn't be created. I have found many StackOverflow questions related to this, but in troubleshooting nearly all permutations of solutions, I couldn't resolve the issue. I created the three Dbs (dev, prod, test), created the user with all access privileges to these dbs, and ran rake db:create. I'm running Mac OS X Lion, MySQL 5.5.28, Rails 2.3.5, Ruby 1.8.7. Here are my settings development: adapter: mysql encoding: utf8 database: adva_development username: adva password: **** host: localhost socket: /tmp/mysql.sock Here's the error: Couldn't create database for {"adapter"=>"mysql", "username"=>"adva", "host"=>"localhost", "encoding"=>"utf8", "database"=>"adva_development", "socket"=>"/tmp/mysql.sock", "password"=>"****"}, charset: utf8, collation: utf8_unicode_ci (if you set the charset manually, make sure you have a matching collation) I have done the following troubleshooting: Verified user and password are correct, and the user has access to the DB. (Double checked user access with SELECT * FROM mysql.db WHERE Db = 'adva_development' \G; User has all privileges.) Verify the socket is correct. I don't really understand sockets, but I can plainly see it at /tmp/mysql.sock. Checked collation and character set. I found out I had created the DB in latin charset and collation, so I recreated them. I ran show variables like "collation_database"; and show variables like "character_set_database"; and came back with utf8 and utf8_unicode_ci respectively. I followed the instructions in this question. After uninstalling mysql gem, I ran the following but came up with the same error: gem install --no-rdoc --no-ri mysql -- --with-mysql-dir=/usr/local/mysql-5.5.28-osx10.6-x86_64/bin --with-mysql-config=/usr/local/mysql-5.5.28-osx10.6-x86_64/bin/mysql_config Following Matt's suggestion, here's what a rake --trace db:create reveals: ** Invoke db:create (first_time) ** Invoke db:load_config (first_time) ** Invoke rails_env (first_time) ** Execute rails_env ** Execute db:load_config ** Execute db:create Couldn't create database for {"database"=>"adva_development", "adapter"=>"mysql", "host"=>"127.0.0.1", "password"=>"woof2adva", "username"=>"adva", "encoding"=>"utf8"}, charset: utf8, collation: utf8_unicode_ci (if you set the charset manually, make sure you have a matching collation) After 3 days and six or seven hours, I have pretty much run out of options. I tried various random things, like replacing localhost with 127.0.0.1 to no avail. Could there be something wrong related to my specific environment? Mac OS X Lion + MySQL 5.5.28? I plan on trying on setting up everything in a Linux environment. Thanks!

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• How do I sync a subset of tables between two databases on the same mysql database server

  - by Mike

  would like to be able to sync a subset of tables between two mysql databases that are running on the same server. One of the databases acts as the master where inserts, updates and deletes can be made. The second database uses those same tables for read-only operations. I do not want to use federated tables to achieve this. The long term goal will be to separate the 2 databases to multiple servers, The second database that has the subset of tables as read-only may also be replicated a few times over to distribute geographically for load and performance purposes each with unqiue data.... Once that is achieved, I plan to use binlog to replicate those specific tables on the secondary databases. In the meantime, I'd like to keep these tables in sync. Is there a more elegant way to do this than other than using a cronjob and mysqldump?

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• MySQL AND alternative for eatch table in a join

  - by Scott

  I have a simple join in a query however I need to have a condition on both of the tables "confirmed='yes'" but if one of the tables doesn't have any that match the query returns with no rows. Database: .----------parties----------. | id - party_id - confirmed | |---------------------------| | 1 1 yes | | 1 2 no | | 1 3 no | +---------------------------+ .-----------events----------. | id - event_id - confirmed | |---------------------------| | 1 1 no | +---------------------------+ Query: SELECT p.party_id, e.event_id FROM parties p LEFT JOIN events e ON p.id=e.id WHERE p.id = '1' AND p.party_id IN (1,2,3) AND e.event_id IN (1) AND p.confirmed='yes' AND e.confirmed='yes' It returns nothing but I want it to return party_id 1 with a empty event_id. I hope this make sense and I not missing anything, Thanks for your help!

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• mysql count(*) left join group by - the number of files in a folder

  - by Flavius

  Hi I have the following tables CREATE TABLE `files` ( `fileid` int(11) NOT NULL AUTO_INCREMENT, `filename` varchar(255) NOT NULL, `filesize` int(11) NOT NULL, `folder` int(11) NOT NULL, PRIMARY KEY (`fileid`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; CREATE TABLE `folders` ( `directoryid` int(11) NOT NULL AUTO_INCREMENT, `directoryname` varchar(255) NOT NULL, PRIMARY KEY (`directoryid`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; How to get a list of all folders and the number of files they hold, including folders who have no (zero) files? Recursion must not be taken into account. Found it select folders.directoryid, folders.directoryname, count(files.fileid) as no_files from folders left join files on files.folder = folders.directoryid group by folders.directoryid, folders.directoryname I hope it will help someone.

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• Counting multiple rows in MySQL in one query

  - by diggersworld

  I currently have a table which stores a load of statistics such as views, downloads, purchases etc. for a multiple number of items. To get a single operation count on each item I can use the following query: SELECT , COUNT() FROM stats WHERE operation = 'view' GROUP BY item_id This gives me all the items and a count of their views. I can then change 'view' to 'purchase' or 'download' for the other variables. However this means three separate calls to the database. Is it possible to get all three in one go?

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• MySQL - Exclude rows from Select based on duplication of two columns

  - by Carson C.

  I am attempting to narrow results of an existing complex query based on conditional matches on multiple columns within the returned data set. I'll attempt to simplify the data as much as possible here. Assume that the following table structure represents the data that my existing complex query has already selected (here ordered by date): +----+-----------+------+------------+ | id | remote_id | type | date | +----+-----------+------+------------+ | 1 | 1 | A | 2011-01-01 | | 3 | 1 | A | 2011-01-07 | | 5 | 1 | B | 2011-01-07 | | 4 | 1 | A | 2011-05-01 | +----+-----------+------+------------+ I need to select from that data set based on the following criteria: If the pairing of remote_id and type is unique to the set, return the row always If the pairing of remote_id and type is not unique to the set, take the following action: Of the sets of rows for which the pairing of remote_id and type are not unique, return only the single row for which date is greatest and still less than or equal to now. So, if today is 2010-01-10, I'd like the data set returned to be: +----+-----------+------+------------+ | id | remote_id | type | date | +----+-----------+------+------------+ | 3 | 1 | A | 2011-01-07 | | 5 | 1 | B | 2011-01-07 | +----+-----------+------+------------+ For some reason I'm having no luck wrapping my head around this one. I suspect the answer lies in good application of group_by, but I just can't grasp it. Any help is greatly appreciated!

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• MySQL AND alternative for each table in a join

  - by Scott

  I have a simple join in a query however I need to have a condition on both of the tables "confirmed='yes'" but if one of the tables doesn't have any that match the query returns with no rows. Database: .----------parties----------. | id - party_id - confirmed | |---------------------------| | 1 1 yes | | 1 2 no | | 1 3 no | +---------------------------+ .-----------events----------. | id - event_id - confirmed | |---------------------------| | 1 1 no | +---------------------------+ Query: SELECT p.party_id, e.event_id FROM parties p LEFT JOIN events e ON p.id=e.id WHERE p.id = '1' AND p.party_id IN (1,2,3) AND e.event_id IN (1) AND p.confirmed='yes' AND e.confirmed='yes' It returns nothing but I want it to return party_id 1 with a empty event_id. I hope this make sense and I not missing anything, Thanks for your help!

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• MySQL: List rows who have one but not another many-to-many relationship

  - by Svish

  Not quite sure how to ask or define this, but can't figure it out. I have three tables like this: persons person_id, first_name, last_name hobbies hobby_id, name persons_hobbies person_id, hobby_id I need to make two lists. Persons that have both hobby A and B, and persons that have hobby A but not B. How can I write these two queries? Can't figure out how to do this with joining and all...

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• MySQL, how to use returned data?

  - by aejo

  Well, I know there is a funciton mysql_fetch_array() and we can use it like this: while ($row = mysql_fetch_array($result)) { echo $row['name'] . "<br />"; } But is there any other way? For example, if there is only one element that can be returned, and not an array. Thanks)

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• Mysql multiple row count?

  - by Steven

  Hello, I have a database full of rows like id,action,date 2,2,2010-03-01 3,2,2010-03-01 4,3,2010-03-01 5,3,2010-03-01 6,4,2010-02-01 7,4,2010-02-01 And I want to select all the count all the 2's and all the 3's and all the 4's. But I don't want to have to do 3 different SELECT COUNT() commands, is there a way to do this in a single command? Note, I want to display this as something like Action 2 = 2 Action 3 = 2 Action 4 = 2 (etc etc). And I will also need to specific a date (so it only counts all the 2,3,4,etc for dates between 2010-02-03 and 2010-03-01 for example)

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• MySql Union not getting executed in a view

  - by aLL0i

  Hi, I am trying to create a view for a UNION of 2 select statements that I have created. The UNION is working fine when executed individually But the problem is only the 1st part of the UNION is getting executed when I am executing it as a view. The query I am using is as below SELECT DISTINCT products.pid AS id, products.pname AS name, products.p_desc AS description, products.p_loc AS location, products.p_uid AS userid, products.isaproduct AS whatisit FROM products UNION SELECT DISTINCT services.s_id AS id, services.s_name AS name, services.s_desc AS description, services.s_uid AS userid, services.s_location AS location, services.isaservice AS whatisit FROM services WHERE services.s_name The above works fine when i execute it separately. But when I use it as a view, it does not give me the results of the services part. Could someone please help me with this?

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• Scripting Language Sessions at Oracle OpenWorld and MySQL Connect, 2012

  - by cj

  This posts highlights some great scripting language sessions coming up at the Oracle OpenWorld and MySQL Connect conferences. These events are happening in San Francisco from the end of September. You can search for other interesting conference sessions in the Content Catalog. Also check out what is happening at JavaOne in that event's Content Catalog (I haven't included sessions from it in this post.) To find the timeslots and locations of each session, click their respective link and check the "Session Schedule" box on the top right. GEN8431 - General Session: What’s New in Oracle Database Application Development This general session takes a look at what’s been new in the last year in Oracle Database application development tools using the latest generation of database technology. Topics range from Oracle SQL Developer and Oracle Application Express to Java and PHP. (Thomas Kyte - Architect, Oracle) BOF9858 - Meet the Developers of Database Access Services (OCI, ODBC, DRCP, PHP, Python) This session is your opportunity to meet in person the Oracle developers who have built Oracle Database access tools and products such as the Oracle Call Interface (OCI), Oracle C++ Call Interface (OCCI), and Open Database Connectivity (ODBC) drivers; Transparent Application Failover (TAF); Oracle Database Instant Client; Database Resident Connection Pool (DRCP); Oracle Net Services, and so on. The team also works with those who develop the PHP, Ruby, Python, and Perl adapters for Oracle Database. Come discuss with them the features you like, your pains, and new product enhancements in the latest database technology. CON8506 - Syndication and Consolidation: Oracle Database Driver for MySQL Applications This technical session presents a new Oracle Database driver that enables you to run MySQL applications (written in PHP, Perl, C, C++, and so on) against Oracle Database with almost no code change. Use cases for such a driver include application syndication such as interoperability across a relationship database management system, application migration, and database consolidation. In addition, the session covers enhancements in database technology that enable and simplify the migration of third-party databases and applications to and consolidation with Oracle Database. Attend this session to learn more and see a live demo. (Srinath Krishnaswamy - Director, Software Development, Oracle. Kuassi Mensah - Director Product Management, Oracle. Mohammad Lari - Principal Technical Staff, Oracle ) CON9167 - Current State of PHP and MySQL Together, PHP and MySQL power large parts of the Web. The developers of both technologies continue to enhance their software to ensure that developers can be satisfied despite all their changing and growing needs. This session presents an overview of changes in PHP 5.4, which was released earlier this year and shows you various new MySQL-related features available for PHP, from transparent client-side caching to direct support for scaling and high-availability needs. (Johannes Schlüter - SoftwareDeveloper, Oracle) CON8983 - Sharding with PHP and MySQL In deploying MySQL, scale-out techniques can be used to scale out reads, but for scaling out writes, other techniques have to be used. To distribute writes over a cluster, it is necessary to shard the database and store the shards on separate servers. This session provides a brief introduction to traditional MySQL scale-out techniques in preparation for a discussion on the different sharding techniques that can be used with MySQL server and how they can be implemented with PHP. You will learn about static and dynamic sharding schemes, their advantages and drawbacks, techniques for locating and moving shards, and techniques for resharding. (Mats Kindahl - Senior Principal Software Developer, Oracle) CON9268 - Developing Python Applications with MySQL Utilities and MySQL Connector/Python This session discusses MySQL Connector/Python and the MySQL Utilities component of MySQL Workbench and explains how to write MySQL applications in Python. It includes in-depth explanations of the features of MySQL Connector/Python and the MySQL Utilities library, along with example code to illustrate the concepts. Those interested in learning how to expand or build their own utilities and connector features will benefit from the tips and tricks from the experts. This session also provides an opportunity to meet directly with the engineers and provide feedback on your issues and priorities. You can learn what exists today and influence future developments. (Geert Vanderkelen - Software Developer, Oracle) BOF9141 - MySQL Utilities and MySQL Connector/Python: Python Developers, Unite! Come to this lively discussion of the MySQL Utilities component of MySQL Workbench and MySQL Connector/Python. It includes in-depth explanations of the features and dives into the code for those interested in learning how to expand or build their own utilities and connector features. This is an audience-driven session, so put on your best Python shirt and let’s talk about MySQL Utilities and MySQL Connector/Python. (Geert Vanderkelen - Software Developer, Oracle. Charles Bell - Senior Software Developer, Oracle) CON3290 - Integrating Oracle Database with a Social Network Facebook, Flickr, YouTube, Google Maps. There are many social network sites, each with their own APIs for sharing data with them. Most developers do not realize that Oracle Database has base tools for communicating with these sites, enabling all manner of information, including multimedia, to be passed back and forth between the sites. This technical presentation goes through the methods in PL/SQL for connecting to, and then sending and retrieving, all types of data between these sites. (Marcelle Kratochvil - CTO, Piction) CON3291 - Storing and Tuning Unstructured Data and Multimedia in Oracle Database Database administrators need to learn new skills and techniques when the decision is made in their organization to let Oracle Database manage its unstructured data. They will face new scalability challenges. A single row in a table can become larger than a whole database. This presentation covers the techniques a DBA needs for managing the large volume of data in a standard Oracle Database instance. (Marcelle Kratochvil - CTO, Piction) CON3292 - Using PHP, Perl, Visual Basic, Ruby, and Python for Multimedia in Oracle Database These five programming languages are just some of the most popular ones in use at the moment in the marketplace. This presentation details how you can use them to access and retrieve multimedia from Oracle Database. It covers programming techniques and methods for achieving faster development against Oracle Database. (Marcelle Kratochvil - CTO, Piction) UGF5181 - Building Real-World Oracle DBA Tools in Perl Perl is not normally associated with building mission-critical application or DBA tools. Learn why Perl could be a good choice for building your next killer DBA app. This session draws on real-world experience of building DBA tools in Perl, showing the framework and architecture needed to deal with portability, efficiency, and maintainability. Topics include Perl frameworks; Which Comprehensive Perl Archive Network (CPAN) modules are good to use; Perl and CPAN module licensing; Perl and Oracle connectivity; Compiling and deploying your app; An example of what is possible with Perl. (Arjen Visser - CEO & CTO, Dbvisit Software Limited) CON3153 - Perl: A DBA’s and Developer’s Best (Forgotten) Friend This session reintroduces Perl as a language of choice for many solutions for DBAs and developers. Discover what makes Perl so successful and why it is so versatile in our day-to-day lives. Perl can automate all those manual tasks and is truly platform-independent. Perl may not be in the limelight the way other languages are, but it is a remarkable language, it is still very current with ongoing development, and it has amazing online resources. Learn what makes Perl so great (including CPAN), get an introduction to Perl language syntax, find out what you can use Perl for, hear how Oracle uses Perl, discover the best way to learn Perl, and take away a small Perl project challenge. (Arjen Visser - CEO & CTO, Dbvisit Software Limited) CON10332 - Oracle RightNow CX Cloud Service’s Connect PHP API: Intro, What’s New, and Roadmap Connect PHP is a public API that enables developers to build solutions with the Oracle RightNow CX Cloud Service platform. This API is used primarily by developers working within the Oracle RightNow Customer Portal Cloud Service framework who are looking to gain access to data and services hosted by the Oracle RightNow CX Cloud Service platform through a backward-compatible API. Connect for PHP leverages the same data model and services as the Connect Web Services for SOAP API. Come to this session to get an introduction and learn what’s new and what’s coming up. (Mark Rhoads - Senior Principal Applications Engineer, Oracle. Mark Ericson - Sr. Principle Product Manager, Oracle) CON10330 - Oracle RightNow CX Cloud Service APIs and Frameworks Overview Oracle RightNow CX Cloud Service APIs are available in the following areas: desktop UI, Web services, customer portal, PHP, and knowledge. These frameworks provide access to Oracle RightNow CX Cloud Service’s Connect Common Object Model and custom objects. This session provides a broad overview of capabilities in all these areas. (Mark Ericson - Sr. Principle Product Manager, Oracle)

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• How can I stop an auto-generated Linq to SQL class from loading ALL data?

  - by Gary McGill

  I have an ASP.NET MVC project, much like the NerdDinner tutorial example. (I'm using MVC 2, but followed the NerdDinner tutorial in order to create it). As per the instructions in part 3 of the tutorial, I've created a Linq-to-SQL model of my database by creating a "Linq to SQL Classes" (.dbml) surface, and dropping my database tables onto it. The designer has automatically added relationships between the generated classes based on my database tables. Let's say that my classes are as per the NerdDinner example, so I have Dinner and RSVP tables, where each Dinner record is associated with many RSVP records - hence in the generated classes, the Dinner object has a RSVPs property which is a list of RSVP objects. My problem is this: it appears (and I'd be gladly proved wrong on this) that as soon as I access a Dinner object, it's loading all of the corresponding RSVP objects, even if I don't use the RSVPs member. First question: is this really the default behavior for the generated classes? In my particular situation, the object graph contains many more tables (which have an order of magnitude more records), and so this is disastrous behaviour - I'd be loading tons of data when all I want to do is show the details of a single parent record. Second question: are there any properties exposed through the designer UI that would let me modify this behavior? (I can't find any). Third question: I've seen a description of how to control the loading of related records in a DataContext by using a DataShape object associated with the DataContext. Is that what I'm meant to do, and if so are there any tutorials like the NerdDinner one that would show not only how to do it, but also suggest a 'pattern' for normal use?

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• How can I remove an "ALMOST" Duplicate using LINQ? ( OR SQL? )

  - by Atomiton

  This should be and easy one for the LINQ gurus out there. I'm doing a complex Query using UNIONS and CONTAINSTABLE in my database to return ranked results to my application. I'm getting duplicates in my returned data. This is expected. I'm using CONTAINSTABLE and CONTAINS to get all the results I need. CONTAINSTABLE is ranked by SQL and CONTAINS (which is run only on the Keywords field ) is hard-code-ranked by me. ( Sorry if that doesn't make sense ) Anyway, because the tuples aren't identical ( their rank is different ) a duplicate is returned. I figure the best way to deal with this is use LINQ. I know I'll be using the Distinct() extension method, but do I have to implement the IEqualityComparer interface? I'm a little fuzzy on how to do this. For argument's sake, say my resultset is structured like this class: class Content { ContentID int //KEY Rank int Description String } If I have a List<Content> how would I write the Distinct() method to exclude Rank? Ideally I'd like to keep the Content's highest Rank. SO, if one Content's RAnk is 112 and the other is 76. I'd like to keep the 112 rank. Hopefully I've given enough information.

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• What is the return type for a anonymous linq query select? What is the best way to send this data ba

  - by punkouter

  This is a basic question. I have the basic SL4/RIA project set up and I want to create a new method in the domain service and return some data from it. I am unsure the proper easiest way to do this.. Should I wrap it up in a ToList()? I am unclear how to handle this anonymous type that was create.. what is the easiest way to return this data? public IQueryable<ApplicationLog> GetApplicationLogsGrouped() { var x = from c in ObjectContext.ApplicationLogs let dt = c.LogDate group c by new { y = dt.Value.Year, m = dt.Value.Month, d = dt.Value.Day } into mygroup select new { aaa = mygroup.Key, ProductCount = mygroup.Count() }; return x; // return this.ObjectContext.ApplicationLogs.Where(r => r.ApplicationID < 50); } Cannot implicitly convert type 'System.Linq.IQueryable<AnonymousType#1>' to 'System.Linq.IQueryable<CapRep4.Web.ApplicationLog>'. An explicit conversion exists (are you missing a cast?) 58 20 CapRep4.Web

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• LINQ to SQL - Why can't you use a WHERE after an ORDER BY?

  - by MCS

  The following code: // select all orders var orders = from o in FoodOrders where o.STATUS = 1 order by o.ORDER_DATE descending select o; // if customer id is specified, only select orders from specific customer if (customerID!=null) { orders = orders.Where(o => customerID.Equals(o.CUSTOMER_ID)); } gives me the following error: Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Linq.IOrderedQueryable'. An explicit conversion exists (are you missing a cast?) I fixed the error by doing the sorting at the end: // select all orders var orders = from o in FoodOrders where o.STATUS = 1 select o; // if customer id is specified, only select orders from specific customer if (customerID!=null) { orders = orders.Where(o => customerID.Equals(o.CUSTOMER_ID)); } // I'm forced to do the ordering here orders = orders.OrderBy(o => o.ORDER_DATE).Reverse(); But I'm wondering why is this limitation in place? What's the reason the API was designed in such a way that you can't add a where constraint after using an order by operator?

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• LINQ to Entities question about orderby and null collections.

  - by Chevex

  I am currently developing a forum. I am new to LINQ and EF. In my forum I have a display that shows a list of topics with the most recent topics first. The problem is that "most recent" is relative to the topic's replies. So I don't want to order the list by the topic's posted date, rather I want to order the list by the topic's last reply's posted date. So that topics with newer replies pop back to the top of the list. This is rather simple if I knew that every topic had at least one reply; I would just do this: var topicsQuery = from x in board.Topics orderby x.Replies.Last().PostedDate descending select x; However, in many cases the topic has no replies. In which case I would like to use the topic's posted date instead. Is there a way within my linq query to order by x.PostedDate in the event that the topic has no replies? I'm getting confused by this and any help would be appreciated. With the above query, it breaks on topics with no replies because of the x.Replies.Last() which assumes there are replies. LastOrDefault() doesn't work because I need to access the PostedDate property which also assumes a reply exists. Thanks in advance for any insight.

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• How to add second JOIN clause in Linq To Sql?

  - by Refracted Paladin

  I am having a lot of trouble coming up with the Linq equivalent of this legacy stored procedure. The biggest hurdle is it doesn't seem to want to let me add a second 'clause' on the join with tblAddress. I am getting a Cannot resolve method... error. Can anyone point out what I am doing wrong? Below is, first, the SPROC I need to convert and, second, my LINQ attempt so far; which is FULL OF FAIL! Thanks SELECT dbo.tblPersonInsuranceCoverage.PersonInsuranceCoverageID, dbo.tblPersonInsuranceCoverage.EffectiveDate, dbo.tblPersonInsuranceCoverage.ExpirationDate, dbo.tblPersonInsuranceCoverage.Priority, dbo.tblAdminInsuranceCompanyType.TypeName AS CoverageCategory, dbo.tblBusiness.BusinessName, dbo.tblAdminInsuranceType.TypeName AS TypeName, CASE WHEN dbo.tblAddress.AddressLine1 IS NULL THEN '' ELSE dbo.tblAddress.AddressLine1 END + ' ' + CASE WHEN dbo.tblAddress.CityName IS NULL THEN '' ELSE '<BR>' + dbo.tblAddress.CityName END + ' ' + CASE WHEN dbo.tblAddress.StateID IS NULL THEN '' WHEN dbo.tblAddress.StateID = 'ns' THEN '' ELSE dbo.tblAddress.StateID END AS Address FROM dbo.tblPersonInsuranceCoverage LEFT OUTER JOIN dbo.tblInsuranceCompany ON dbo.tblPersonInsuranceCoverage.InsuranceCompanyID = dbo.tblInsuranceCompany.InsuranceCompanyID LEFT OUTER JOIN dbo.tblBusiness ON dbo.tblBusiness.BusinessID = dbo.tblInsuranceCompany.BusinessID LEFT OUTER JOIN dbo.tblAddress ON dbo.tblAddress.BusinessID = dbo.tblBusiness.BusinessID and tblAddress.AddressTypeID = 'b' LEFT OUTER JOIN dbo.tblAdminInsuranceCompanyType ON dbo.tblPersonInsuranceCoverage.InsuranceCompanyTypeID = dbo.tblAdminInsuranceCompanyType.InsuranceCompanyTypeID LEFT OUTER JOIN dbo.tblAdminInsuranceType ON dbo.tblPersonInsuranceCoverage.InsuranceTypeID = dbo.tblAdminInsuranceType.InsuranceTypeID WHERE tblPersonInsuranceCoverage.PersonID = @PersonID var coverage = from insuranceCoverage in context.tblPersonInsuranceCoverages where insuranceCoverage.PersonID == personID join insuranceCompany in context.tblInsuranceCompanies on insuranceCoverage.InsuranceCompanyID equals insuranceCompany.InsuranceCompanyID join address in context.tblAddresses on insuranceCompany.tblBusiness.BusinessID equals address.BusinessID where address.AddressTypeID = 'b' select new { insuranceCoverage.PersonInsuranceCoverageID, insuranceCoverage.EffectiveDate, insuranceCoverage.ExpirationDate, insuranceCoverage.Priority, CoverageCategory = insuranceCompany.tblAdminInsuranceCompanyType.TypeName, insuranceCompany.tblBusiness.BusinessName, TypeName = insuranceCoverage.InsuranceTypeID, Address = };

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