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• jpa join query on a subclass

  - by Brian

  I have the following relationships in JPA (hibernate). Object X has two subclasses, Y and Z. Object A has a manyToOne relationship to object X. (Note, this is a one-sided relationship so object X cannot see object A). Now, I want to get the max value of a column in object A, but only where the relationship is of a specific subtype, ie...Y. So, that equates to...get the max value of column1 in object A, across all instances of A where they have a relationship with Y. Is this possible? I'm a bit lost as how to query it. I was thinking of something like: String query = "SELECT MAX(a.columnName) FROM A a join a.x; Query query = super.entityManager.createQuery(query); query.execute(); However that doesn't take account of the subclass of X...so I'm a bit lost. Any help would be much appreciated.

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• Check if a class is subclass of another class in Java

  - by craesh

  Hi! I'm playing around with Java's reflection API and trying to handle some fields. Now I'm stuck with identifying the type of my fields. Strings are easy, just do myField.getType().equals(String.class). The same applies for other non-derived classes. But how do I check derived classes? E.g. LinkedList as subclass of List. I can't find any isSubclassOf(...) or extends(...) method. Do I need to walk through all getSuperClass() and find my supeclass by my own? Thanks! craesh

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• ruby subclass filter

  - by Nik

  Hey! Maybe I am getting the idea of a subclass wrong, but I have a Person model and it has an attrib called "age" so Person.first.age #=> '20' Now I want to have a model that's basically persons 55 or older so I know I can have a class like this: class Senior < Person end But how can I "pre-filter" the Senior class so that every object belonging to that class has age = 55? Senior.first.age #=> 56 Thanks!

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• Abstract class get parameter from implementing subclass?

  - by soren.qvist

  I'm wondering if there is way to do this without breaking encapsulation, I want the abstract class to rely on parameters defined in the implementing subclass. Like so: public abstract class Parent { private int size; private List<String> someList; public Parent() { size = getSize(); someList = new ArrayList<String>(size); } public abstract int getSize(); } public class Child extends Parent { @Override public int getSize() { return 5; } } Is this ugly? Is there a better way? And perhaps more importantly, is this even a good idea?

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• AttributeError in my Python program regarding classes

  - by Axel Finkel

  I'm doing an exercise out of the Python book that involves creating a class and a subclass. I am getting the following error when I try to run the program: AttributeError: 'Customer' object has no attribute 'name', when it tries to go through this bit of code: self.name.append(name) As this is my first time dealing with classes and objects in Python, I'm sure I am making some overt mistake somewhere, but I can't seem to figure it out. I've looked over the documentation for creating classes and writing member functions, and it looks correct, but it is obviously not. I want the Customer subclass to inherit the name, address, and telephone attributes from the Person superclass, but it doesn't seem to be doing so? Here is my code: class Person: def __init__(self): self.name = None self.address = None self.telephone = None def changeName(self, name): self.name.append(name) def changeAddress(self, address): self.address.append(address) def changeTelephone(self, telephone): self.telephone.append(telephone) class Customer(Person): def __init__(self): self.customerNumber = None self.onMailingList = False def changeCustomerNumber(self, customerNumber): self.customerNumber.append(customerNumber) def changeOnMailingList(): if onMailingList == False: onMailingList == True else: onMailingList == False def main(): customer1 = Customer() name = 'Bob Smith' address = '123 Somewhere Road' telephone = '111 222 3333' customerNumber = '12345' customer1.changeName(name) customer1.changeAddress(address) customer1.changeTelephone(telephone) customer1.changeCustomerNumber(customerNumber) print("Customer name: " + customer1.name) print("Customer address: " + customer1.address) print("Customer telephone number: " + customer1.telephone) print("Customer number: " + customer1.customerNumber) print("On mailing list: " + customer1.OnMailingList) customer1.changeOnMailingList() print("On mailing list: " + customer1.OnMailingList) main()

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• Can DirectX 3D Meshes be merged, or joined together

  - by Bubba

  C# programmer, beginner DirectX. Have created 2 meshes using Mesh.Cylinder but need to combine them into a single mesh. Is that possible?

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• Fluent NHibernate - How to map a non nullable foreign key that exists in two joined tables

  - by vakman

  I'm mapping a set of membership classes for my application using Fluent NHibernate. I'm mapping the classes to the asp.net membership database structure. The database schema relevant to the problem looks like this: ASPNET_USERS UserId PK ApplicationId FK NOT NULL other user columns ... ASPNET_MEMBERSHIP UserId PK,FK ApplicationID FK NOT NULL other membership columns... There is a one to one relationship between these two tables. I'm attempting to join the two tables together and map data from both tables to a single 'User' entity which looks like this: public class User { public virtual Guid Id { get; set; } public virtual Guid ApplicationId { get; set; } // other properties to be mapped from aspnetuser/membership tables ... My mapping file is as follows: public class UserMap : ClassMap<User> { public UserMap() { Table("aspnet_Users"); Id(user => user.Id).Column("UserId").GeneratedBy.GuidComb(); Map(user => user.ApplicationId); // other user mappings Join("aspnet_Membership", join => { join.KeyColumn("UserId"); join.Map(user => user.ApplicationId); // Map other things from membership to 'User' class } } } If I try to run with the code above I get a FluentConfiguration exception Tried to add property 'ApplicationId' when already added. If I remove the line "Map(user = user.ApplicationId);" or change it to "Map(user = user.ApplicationId).Not.Update().Not.Insert();" then the application runs but I get the following exception when trying to insert a new user: Cannot insert the value NULL into column 'ApplicationId', table 'ASPNETUsers_Dev.dbo.aspnet_Users'; column does not allow nulls. INSERT fails. The statement has been terminated. And if I leave the .Map(user = user.ApplicationId) as it originally was and make either of those changes to the join.Map(user = user.ApplicationId) then I get the same exception above except of course the exception is related to an insert into the aspnet_Membership table So... how do I do this kind of mapping assuming I can't change my database schema?

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• MySQL - How do I inner join sorting the joined data

  - by Gary

  I'm trying to write a report which will join a person, their work, and their hourly wage at the time of work. I cannot seem to figure out the best way to join the person's cost when the date is less than the date of the work. Let's say a person cost $30 per hour at the start of the year then got a $10 raise o Feb 5 and another on Mar 1. 01/01/2010 $30.00 (per hour) 02/05/2010 $40.00 03/01/2010 $45.00 The person put in hours several days which span the rasies. 01/05/2010 10 hours (should be at $30/hr) 01/27/2010 5 hours (again at $30) 02/10/2010 10 hours (at $40/hr) 03/03/2010 5 hours (at $45/hr) I'm trying to write one SQL statement which will pull the hours, the cost per hour, and the hours*cost. The cost is the hourly rate last entered into the system so the cost date is less than the work date, ordered by cost date limit 1. SELECT person.id, person.name, work.hours, person_costs.value, work.hours * person_costs.value AS value FROM person INNER JOIN work ON (person.id = work.person_id) INNER JOIN person_costs ON (person.id = person_costs.person_id AND person_costs.date < work.date) WHERE person.id = 1234 ORDER BY work.date ASC The problem I'm having, the person_costs isn't ordered by date in descending order. It's pulling out "any" value (naturally sorted by record position) which matches the condition. How do I select the first person_cost value which is older than the work date? Thanks!

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• Regex: Matching a space-joined list of words, excluding last whitespace

  - by Jesper

  How would I match a space separated list of words followed by whitespace and some optional numbers? I have this: >>> import re >>> m = re.match('(?P<words>(\w+\s+)+)(?P<num>\d+)?\r\n', 'Foo Bar 12345\r\n') >>> m.groupdict() {'num': '12345', 'words': 'Foo Bar '} I'd like the words group to not include the last whitespace(s) but I can't figure this one out. I could do a .strip() on the result but that's not as much fun :) Some strings to test and wanted result: 'Foo & Bar 555\r\n' => {'num': '555', 'words': 'Foo & Bar'} 'Hello World\r\n' => {'num': None, 'words': 'Hello World'} 'Spam 99\r\n' => {'num': 99, 'words': 'Spam'} 'Number 1 666\r\n' => {'num': 666, 'words': 'Number 1'}

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• Linq is returning too many results when joined

  - by KallDrexx

  In my schema I have two database tables. relationships and relationship_memberships. I am attempting to retrieve all the entries from the relationship table that have a specific member in it, thus having to join it with the relationship_memberships table. I have the following method in my business object: public IList<DBMappings.relationships> GetRelationshipsByObjectId(int objId) { var results = from r in _context.Repository<DBMappings.relationships>() join m in _context.Repository<DBMappings.relationship_memberships>() on r.rel_id equals m.rel_id where m.obj_id == objId select r; return results.ToList<DBMappings.relationships>(); } _Context is my generic repository using code based on the code outlined here. The problem is I have 3 records in the relationships table, and 3 records in the memberships table, each membership tied to a different relationship. 2 membership records have an obj_id value of 2 and the other is 3. I am trying to retrieve a list of all relationships related to object #2. When this linq runs, _context.Repository<DBMappings.relationships>() returns the correct 3 records and _context.Repository<DBMappings.relationship_memberships>() returns 3 records. However, when the results.ToList() executes, the resulting list has 2 issues: 1) The resulting list contains 6 records, all of type DBMappings.relationships(). Upon further inspection there are 2 for each real relationship record, both are an exact copy of each other. 2) All relationships are returned, even if m.obj_id == 3, even though objId variable is correctly passed in as 2. Can anyone see what's going on because I've spent 2 days looking at this code and I am unable to understand what is wrong. I have joins in other linq queries that seem to be working great, and my unit tests show that they are still working, so I must be doing something wrong with this. It seems like I need an extra pair of eyes on this one :)

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• How to output JOINed tables?

  - by ilhan

  $id=(int)$_GET["id"]; $result = mysql_query("SELECT questionstable.*, categorytable.name FROM questionstable INNER JOIN categorytable ON categorytable.id = questionstable.category WHERE id=$id"); $row = mysql_fetch_assoc($result); Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in C:\Program Files\EasyPHP-5.3.4.0\www\scsoru.php on line 33

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• NHibernate mapping for subclasses and joined-subclasses

  - by Husain

  In a project that I am working on, I have the following entities: Analyst, Client and Contractor. Each inherit from a base class User. public abstract class User { public virtual int Id { get; set; } public virtual string Username { get; set; } public virtual string FullName { get; set; } } I then have the other classes inheriting from the base class as: public class Analyst : User { // Empty class. There are no additional properties for an analyst. } public class Client : User { // Empty class. There are no additional properties for a client. } public class Contractor : User { public int TotalJobs { get; set; } public int JobsInProgress { get; set; } } For the above classes, I have the following table structure: USER ---- UserId Username FullName UserType (1 = Analyst, 2 = Client, 3 = Contractor) CONTRACTOR ---------- UserId TotalJobs JobsInProgress There are no tables for Analyst and Client classes. I would like to know how I can write the NHibernate mapping file for the Contractor class. For the other classes, I have created a User mapping file and added Client and Analyst as sub-classes. How can I map the Contractor class?

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• SQL Query Help Part 2 - Add filter to joined tables and get max value from filter

  - by Seth

  I asked this question on SO. However, I wish to extend it further. I would like to find the max value of the 'Reading' column only where the 'state' is of value 'XX' for example. So if I join the two tables, how do I get the row with max(Reading) value from the result set. Eg. SELECT s.*, g1.* FROM Schools AS s JOIN Grades AS g1 ON g1.id_schools = s.id WHERE s.state = 'SA' // how do I get row with max(Reading) column from this result set The table details are: Table1 = Schools Columns: id(PK), state(nvchar(100)), schoolname Table2 = Grades Columns: id(PK), id_schools(FK), Year, Reading, Writing...

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• Using a "vo" for joined data?

  - by keithjgrant

  I'm building a small financial system. Because of double-entry accounting, transactions always come in batches of two or more, so I've got a batch table and a transaction table. (The transaction table has batch_id, account_id, and amount fields, and shared data like date and description are relegated to the batch table). I've been using basic vo-type models for each table so far. Because of this table structure structure, though, transactions will almost always be selected with a join on the batch table. So should I take the selected records and splice them into two separate vo objects, or should I create a "shared" vo that contains both batch and transaction data? There are a few cases in which batch records and/or transaction records. Are there possible pitfalls down the road if I have "overlapping" vo classes?

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• JPA joined column allow every value...

  - by Fabio Beoni

  I'm testing JPA, in a simple case File/FileVersions tables (Master/Details), with OneToMany relation, I have this problem: in FileVersions table, the field "file_id" (responsable for the relation with File table) accepts every values, not only values from File table. How can I use the JPA mapping to limit the input in FileVersion.file_id only for values existing in File.id? My class are File and FileVersion: FILE CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="FILE_ID") private Long id; @Column(name="NAME", nullable = false, length = 30) private String name; //RELATIONS ------------------------------------------- @OneToMany(mappedBy="file", fetch=FetchType.EAGER) private Collection <FileVersion> fileVersionsList; //----------------------------------------------------- FILEVERSION CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="VERSION_ID") private Long id; @Column(name="FILENAME", nullable = false, length = 255) private String fileName; @Column(name="NOTES", nullable = false, length = 200) private String notes; //RELATIONS ------------------------------------------- @ManyToOne(fetch=FetchType.EAGER) @JoinColumn(name="FILE_ID", referencedColumnName="FILE_ID", nullable=false) private File file; //----------------------------------------------------- and this is the FILEVERSION TABLE CREATE TABLE `JPA-Support`.`FILEVERSION` ( `VERSION_ID` bigint(20) NOT NULL AUTO_INCREMENT, `FILENAME` varchar(255) NOT NULL, `NOTES` varchar(200) NOT NULL, `FILE_ID` bigint(20) NOT NULL, PRIMARY KEY (`VERSION_ID`), KEY `FK_FILEVERSION_FILE_ID` (`FILE_ID`) ) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1

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• exclude joined rows from a select

  - by Vaccano

  I have two tables. One has rows with values A-Z and the other has D-G. How do I make a select statement to return only the values A-C, H-Z? (This is, of course a dumbed down version of my real tables and problem.)

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• How to make query on a property from a joined table in Hibernate using Criteria

  - by Palo

  Hello, I have the following mapping: <hibernate-mapping package="server.modules.stats.data"> <class name="User" table="user"> <id name="id"> <generator class="native"></generator> </id> <many-to-one name="address" column="addressId" unique="true" lazy="false" /> </class> <class name="Address" table="address"> <id name="id"> <generator class="native"></generator> </id> <property name="street" /> </class> </hibernate-mapping> How can I do a Criteria query to select all users living on some street? That is create Criteria query for this SQL: Select * from user join address on user.addressId = address.id where address.street='someStreet'

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• Rails: using find method to access joined tables for polymorphic relationships

  - by DJTripleThreat

  Ok, I have a generic TimeSlot model that deals with a start_at and an end_at for time spans. A couple models derive from this but I'm referring to one in this question: AppointmentBlock which is a collection of Appointments. I want to validate an AppointmentBlock such that no other AppointmentBlocks have been scheduled for a particular Employee in the same time frame. Since AppointmentBlock has a polymorphic association with TimeSlot, you have to access the AppointmentBlock's start_at and end_at through the TimeSlot like so: appt_block.time_slot.start_at This means that I need to have some kind of join in my :conditions for my find() method call. Here is my code so far: #inside my appointment_block.rb model validate :employee_not_double_booked def employee_not_double_booked unless self.employee_id # this find's condition is incorrect because I need to join time_slots to get access # to start_at and end_at. How can I do this? blocks = AppointmentBlock.find(:first, :conditions => ['employee_id = ? and (start_at between ? and ? or end_at between ? and ?)', self.employee_id, self.time_slot.start_at, self.time_slot.end_at, self.time_slot.start_at, self.time_slot.end_at]) # pseudo code: # collect a list of appointment blocks that end after this # apointment block starts or start before this appointment # block ends that are also associated with this appointment # blocks assigned employee # if the count is great then 0 the employee has been double # booked. # if a block was found that means this employee is getting # double booked so raise an error errors.add "AppointmentBlock", "has already been scheduled during this time" if blocks end end Since AppointmentBlock doesn't have a start_at or an end_at how can I join with the time_slots table to get those conditions to work?

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• Where clause on joined table used for user defined key/value pairs

  - by Steve Wright

  Our application allows administrators to add “User Properties” in order for them to be able to tailor the system to match their own HR systems. For example, if your company has departments, you can define “Departments” in the Properties table and then add values that correspond to “Departments” such as “Jewelry”, “Electronics” etc… You are then able to assign a department to users. Here is the schema: In this schema, a User can have only one UserPropertyValue per Property, but doesn’t have to have a value for the property. I am trying to build a query that will be used in SSRS 2005 and also have it use the PropertyValues as the filter for users. My query looks like this: SELECT UserLogin, FirstName, LastName FROM Users U LEFT OUTER JOIN UserPropertyValues UPV ON U.ID = UPV.UserID WHERE UPV.PropertyValueID IN (1, 5) When I run this, if the user has ANY of the property values, they are returned. What I would like to have is where this query will return users that have values BY PROPERTY. So if PropertyValueID = 1 is of Department (Jewelry), and PropertyValueID = 5 is of EmploymentType (Full Time), I want to return all users that are in Department Jewelry that are EmployeeType of Full Time, can this be done? Here's a full data example: User A has Department(Jewelry value = 1) and EmploymentType(FullTime value = 5)User B has Department(Electronics value = 2) and EmploymentType(FullTime value = 5)User C has Department(Jewelry value = 1) and EmployementType(PartTime value = 6) My query should only return User A using the above query UPDATE: I should state that this query is used as a dataset in SSRS, so the parameter passed to the query will be @PropertyIDs and it is defined as a multi-value parameter in SSRS. WHERE UPV.PropertyValueID IN (@PropertyIDs)

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• How Can I Join Two DB Tables and Return Lowest Price From Joined Table

  - by Jason

  I have two tables, the first table has the product and the second table the prices. The price table could have more than one price per product but I only want to display the lowest. But I keep getting all the prices returned and I'm having trouble figuring out how to do it. this is what I get returned in my query: SELECT * FROM products AS pr JOIN prices AS p ON pr.id = p.product_id WHERE pr.live = 1 AND p.live = 1 id product1 name description £100 id product1 name description £300 id product1 name description £200 id product2 name description £50 id product2 name description £80 id product2 name description £60 id product3 name description £222 id product3 name description £234 id product3 name description £235 but I'm after: id product1 name description £100 id product2 name description £50 id product3 name description £222 Any help would be appreciated

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• PHP While loop seperating unique categories from multiple 'Joined' tables

  - by Hob

  I'm pretty new to Joins so hope this all makes sense. I'm joining 4 tables and want to create a while loop that spits out results nested under different categories. My Tables categories id | category_name pages id | page_name | category *page_content* id | page_id | image_id images id | thumb_path My current SQL join <?php $all_photos = mysql_query(" SELECT * FROM categories JOIN pages ON pages.category = categories.id JOIN image_pages ON image_pages.page_id = pages.id JOIN images ON images.id = image_pages.image_id ");?> The result I want from a while loop I would like to get something like this.... Category 1 page 1 Image 1, image 2, image 3 page 2 Image 2, image 4 Category 2 page 3 image 1 page 4 image 1, image 2, image 3 I hope that makes sense. Each image can fall under multiple pages and each page can fall under multiple categories. at the moment I have 2 solutions, one which lists each category several times according to the the amount of pages inside them: eg. category 1, page 1, image 1 - category 1, page 1, image 2 etc One that uses a while loop inside another while loop inside another while loop, resulting in 3 sql queries. <?php while($all_page = mysql_fetch_array($all_pages)) { ?> <p><?=$all_page['page_name']?></p> <?php $all_images = mysql_query("SELECT * FROM images JOIN image_pages ON image_pages.page_id = " . $all_page['id'] . " AND image_pages.image_id = images.id"); ?> <div class="admin-images-block clearfix"> <?php while($all_image = mysql_fetch_array($all_images)) { ?> <img src="<?=$all_image['thumb_path']?>" alt="<?=$all_image['title']?>"/> <?php } ?> </div> <?php } } ?

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• MySQL: Limit rows linked to each joined row

  - by SolidSnakeGTI

  Hello, Specifications: MySQL 4.1+ I've certain situation that requires certain result set from MySQL query, let's see the current query first & then ask my question: SELECT thread.dateline AS tdateline, post.dateline AS pdateline, MIN(post.dateline) FROM thread AS thread LEFT JOIN post AS post ON(thread.threadid = post.threadid) LEFT JOIN forum AS forum ON(thread.forumid = forum.forumid) WHERE post.postid != thread.firstpostid AND thread.open = 1 AND thread.visible = 1 AND thread.replycount >= 1 AND post.visible = 1 AND (forum.options & 1) AND (forum.options & 2) AND (forum.options & 4) AND forum.forumid IN(1,2,3) GROUP BY post.threadid ORDER BY tdateline DESC, pdateline ASC As you can see, mainly I need to select dateline of threads from 'thread' table, in addition to dateline of the second post of each thread, that's all under the conditions you see in the WHERE CLAUSE. Since each thread has many posts, and I need only one result per thread, I've used GROUP BY CLAUSE for that purpose. This query will return only one post's dateline with it's related unique thread. My questions are: How to limit returned threads per each forum!? Suppose I need only 5 threads -as a maximum- to be returned for each forum declared in the WHERE CLAUSE 'forum.forumid IN(1,2,3)', how can this be achieved. Is there any recommendations for optimizing this query (of course after solving the first point)? Notes: I prefer not to use sub-queries, but if it's the only solution available I'll accept it. Double queries not recommended. I'm sure there's a smart solution for this situation. Appreciated advice in advance :)

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• Using LEFT JOIN to only selection one joined row

  - by Alex

  I'm trying to LEFT JOIN two tables, to get a list of all rows from TABLE_1 and ONE related row from TABLE_2. I have tried LEFT JOIN and GROUP BY c_id, however I wan't the related row from TABLE_2 to be sorted by isHeadOffice DESC. Here are some sample tables TABLE 1 c_id Name ---------------- 1 USA 2 Canada 3 England 4 France 5 Spain TABLE2 o_id c_id Office isHeadOffice ------------------------------------------------ 1 1 New York 1 2 1 Washington 0 3 1 Boston 0 4 2 Toronto 0 5 3 London 0 6 3 Manchester 1 7 4 Paris 1 8 4 Lyon 0 So what I am trying to get from this would be something like: RESULTS c_id Name Office ---------------------------- 1 USA New York 2 Canada Toronto 3 England Manchester 4 France Paris 5 Spain NULL I'm using PHP & MySQL. Any ideas?

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• Preventing entire JOINed MYSQL query from failing when one field is missing within a WHERE clause

  - by filip o

  I am doing a couple of joins with a variable in the WHERE clause. I'm not sure if I am doing everything as efficiently as I could, or even using the best practices but my issue is that half my tables have data for when tableC.type=500, and the other half don't resulting in the entire query failing. SELECT tableA.value1 , tableB.value2, tableC.value3 FROM tableA JOIN tableB ON tableB.id=tableA.id JOIN tableC ON tableC.id=tableB.id WHERE tableA.category=$var && tableC.type=500; What I would like to happen is to still get tableA.value1 and tableB.value2 even if there is no field in tableC with a type=500. any thoughts? i'm totally stumped as how to approach this...

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• SQL: Limit rows linked to each joined row

  - by SolidSnakeGTI

  Hello, I've certain situation that requires certain result set from MySQL query, let's see the current query first & then ask my question: SELECT thread.dateline AS tdateline, post.dateline AS pdateline, MIN(post.dateline) FROM thread AS thread LEFT JOIN post AS post ON(thread.threadid = post.threadid) LEFT JOIN forum AS forum ON(thread.forumid = forum.forumid) WHERE post.postid != thread.firstpostid AND thread.open = 1 AND thread.visible = 1 AND thread.replycount >= 1 AND post.visible = 1 AND (forum.options & 1) AND (forum.options & 2) AND (forum.options & 4) AND forum.forumid IN(1,2,3) GROUP BY post.threadid ORDER BY tdateline DESC, pdateline ASC As you can see, mainly I need to select dateline of threads from 'thread' table, in addition to dateline of the second post of each thread, that's all under the conditions you see in the WHERE CLAUSE. Since each thread has many posts, and I need only one result per thread, I've used GROUP BY CLAUSE for that purpose. This query will return only one post's dateline with it's related unique thread. My questions are: How to limit returned threads per each forum!? Suppose I need only 5 threads -as a maximum- to be returned for each forum declared in the WHERE CLAUSE 'forum.forumid IN(1,2,3)', how can this be achieved. Is there any recommendations for optimizing this query (of course after solving the first point)? Notes: I prefer not to use sub-queries, but if it's the only solution available I'll accept it. Double queries not recommended. I'm sure there's a smart solution for this situation. I'm using MySQL 4.1+, but if you know the answer for another engine, just share. Appreciated advice in advance :)

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