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  • Nested joins hide table names

    - by Sergio
    Hi: I have three tables: Suppliers, Parts and Types. I need to join all of them while discriminating columns with the same name (say, "id") in the three tables. I would like to successfully run this query: CREATE VIEW Everything AS SELECT Suppliers.name as supplier, Parts.id, Parts.description, Types.typedesc as type FROM Suppliers JOIN (Parts JOIN Types ON Parts.type_id = Types.id) ON Suppliers.id = Parts.supplier_id; My DBMS (sqlite) complains that "there is not such a column (Parts.id)". I guess it forgets table names once the JOIN is done but then how can I refer to the column id that belongs to the table Parts?

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  • How to convert an application to be a database independent app ?

    - by Eslam
    I have a java web application that has informix DB as it's back end database , now i take a decision to make my app work with SqlServer so i changed all the informix related syntax into SqlServer, and i may take a decision in the future to switch into oracle so the pain will be repeated again and again, as a result i decided to make my application a DataBase independent one that's able to work with any DB vendor smoothly, but i have no idea till now about how to do that, so your ideas is welcomed.

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  • Extending Zend DB Table to include BETWEEN and LIMIT.

    - by davykiash
    Am looking for how I can extend the Zend_DB_Table below to accomodate a BETWEEN two dates syntax and LIMIT syntax My current construct is class Model_DbTable_Tablelist extends Zend_Db_Table_Abstract { protected $_name = 'mytable'; $select = $this->select() ->setIntegrityCheck(false) ->from('mytable', array('MyCol1', 'MyDate')); } I want it extended to be equivalent to the query below SELECT MyCol1,MyDate FROM mytable WHERE MyDate BETWEEN '2008-04-03' AND '2009-01-02' LIMIT 0,20 Any ideas?

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  • How can I get the rank of rows relative to total number of rows based on a field?

    - by Arms
    I have a scores table that has two fields: user_id score I'm fetching specific rows that match a list of user_id's. How can I determine a rank for each row relative to the total number of rows, based on score? The rows in the result set are not necessarily sequential (the scores will vary widely from one row to the next). I'm not sure if this matters, but user_id is a unique field. Edit @Greelmo I'm already ordering the rows. If I fetch 15 rows, I don't want the rank to be 1-15. I need it to be the position of that row compared against the entire table by the score property. So if I have 200 rows, one row's rank may be 3 and another may be 179 (these are arbitrary #'s for example only). Edit 2 I'm having some luck with this query, but I actually want to avoid ties SELECT s.score , s.created_at , u.name , u.location , u.icon_id , u.photo , (SELECT COUNT(*) + 1 FROM scores WHERE score > s.score) AS rank FROM scores s LEFT JOIN users u ON u.uID = s.user_id ORDER BY s.score DESC , s.created_at DESC LIMIT 15 If two or more rows have the same score, I want the latest one (or earliest - I don't care) to be ranked higher. I tried modifying the subquery with AND id > s.id but that ended up giving me an unexpected result set and different ties.

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  • LINQtoSQL: Query to return List<String>

    - by ctrlShiftBryan
    I have a LINQ query that returns some object like this... var query = from c in db.Customers where ... select c; Then I do this List<String> list = new List<String>(); foreach (ProgramLanguage c in query) { //GetUL returns a String list.Add(GetUL(c.Property,c.Property2)); } Is there a way to combine into something list this? var query = from c in db.Customers where ... select new { GetUL(c.Property,c.Property2) }).ToList<String>();

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  • Passing Results from SQL to Google Maps API in CodeIgniter

    - by Jason Shultz
    I'm hoping to use google maps on my site. My addresses are stored in a db. I’m pulling up a page where the information is all dynamic. For example: mysite.com/site/business/5 (where 5 is the id of the business). Let’s say I do a query like this: function addressForMap($id) { $this->db->select(‘b.id, b.busaddress, b.buscity, b.buszip’); $this->db->from(‘business as b’); $this->db->where(‘b.id, $id); } How can I output the info to the google maps api correctly so that it display’s the map appropriately? The API interface takes the results like this: $marker['address'] = 'Crescent Park, Palo Alto';

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  • Advanced LINQ Update Statement

    - by user1902490
    I have a data base with Price_old like: Date --- Hour --- Price _____________________________ Jan 1 --- 1 --- $3.0 Jan 1 --- 2 --- $3.1 Jan 1 --- 3 --- $3.3 Jan 1 --- 4 --- $3.15 Jan 2 --- 1 --- $2.95 Jan 2 --- 2 --- $3.2 Jan 2 --- 3 --- $3.05 What I then have is a spreadsheet, with the same structure, that I will be reading into a datatable, I'll call the new datatable Price_New, note that price new may not have all the same date/hours as Price_Old So, I end up with 2 datatables, Price_Old, and Price_New, and what I need to do is update Price_old with the new prices in Price_New, and then commit those new prices to the Database. I am kinda new to LINQ (about 30 mins of experience) and would really appreciate if someone could give me a pointer or two on whether or not this is doing in LINQ and what the best method would be. Thanks

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  • Does clustered index on foreign key column increase join performance vs non-clustered ?

    - by alpav
    In many places it's recommended that clustered indexes are better utilized when used to select range of rows using BETWEEN statement. When I select joining by foreign key field in such a way that this clustered index is used, I guess, that clusterization should help too because range of rows is being selected even though they all have same clustered key value and BETWEEN is not used. Considering that I care only about that one select with join and nothing else, am I wrong with my guess ?

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  • Tool Compare the tables in two different databeses

    - by user191124
    I am using Toad. Frequently i need to compare tables in two different test environments. the tables present in them are same but the data differs. i just need to know what are the differences in the same tables which are in two different data bases.Are there any tools which can be installed on windows and use it to compare. Much appreciate your help:)

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  • Put logic behind generated LinqToSql fields

    - by boris callens
    In a database I use throughout several projects, there is a field that should actually be a boolean but is for reasons nobody can explain to me a field duplicated over two tables where one time it is a char ('Y'/'N') and one time an int (1/0). When I generate a datacontext with LinqToSql the fields off course gets these datatypes. It would be nice if I don't have to drag this stupid choice of datatype throughout the rest of my application. Is there a way to give the generated classes a little bit of logic that just return me return this.equals('Y'); and return this==1; Preferably without having to make an EXTRA field in my partial class. It would be a solution to give the generated field a totally different name that can only be accessed through the partial class and then generate the extra field with the original name with my custom logic in the partial class. I don't know how to alter the accesibility level in my generated class though.. Any suggestions?

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  • Querying with foreign key

    - by theactiveactor
    Say I have 2 tables whose structures are as follows: tableA id | A1 | A2 tableB id | tableA_id (foreign key) | B1 Entries in A have a one-to-many relationship with entries in B. What kind of query operation would I need to achieve "something like this: select all objects from table B where A1="foo""? Basically, apply a query on tableA and from those result, find corresponding dependent objects in tableB

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  • How do I find the top N batters per year?

    - by Drew Stephens
    I'm playing around with the Lahman Baseball Database in a MySQL instance. I want to find the players who topped home runs (HR) for each year. The Batting table has the following (relevant parts) of its schema: +-----------+----------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------+----------------------+------+-----+---------+-------+ | playerID | varchar(9) | NO | PRI | | | | yearID | smallint(4) unsigned | NO | PRI | 0 | | | HR | smallint(3) unsigned | YES | | NULL | | +-----------+----------------------+------+-----+---------+-------+ For each year, every player has an entry (between hundreds and 12k per year, going back to 1871). Getting the top N hitters for a single year is easy: SELECT playerID,yearID,HR FROM Batting WHERE yearID=2009 ORDER BY HR DESC LIMIT 3; +-----------+--------+------+ | playerID | yearID | HR | +-----------+--------+------+ | pujolal01 | 2009 | 47 | | fieldpr01 | 2009 | 46 | | howarry01 | 2009 | 45 | +-----------+--------+------+ But I'm interested in finding the top 3 from every year. I've found solutions like this, describing how to select the top from a category and I've tried to apply it to my problem, only to end up with a query that never returns: SELECT b.yearID, b.playerID, b.HR FROM Batting AS b LEFT JOIN Batting b2 ON (b.yearID=b2.yearID AND b.HR <= b2.HR) GROUP BY b.yearID HAVING COUNT(*) <= 3; Where have I gone wrong?

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  • Are GUID primary keys bad in theory, or just practice?

    - by Yarin
    Whenever I design a database I automatically start with an auto-generating GUID primary key for each of my tables (excepting look-up tables) I know I'll never lose sleep over duplicate keys, merging tables, etc. To me it just makes sense philosophically that any given record should be unique across all domains, and that that uniqueness should be represented in a consistent way from table to table. I realize it will never be the most performant option, but putting performance aside, I'd like to know if there are philosophical arguments against this practice?

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  • how do i connect to MSSQL 2008 database in JAVA with jbbc

    - by shuxer
    Hello I have MSSQL 2008 installed on my local PC, and my java application needs to connect to a mssql database. I am a new to MSSQL and i would like get some help on creating user login for my java application and getting connection via jdbc. So far i tried to create a user login for my app and used following connection string, but i doest work at all. Any help and hint will be appreciated. jdbc:jtds:sqlserver://127.0.0.1:1433/dotcms username="shuxer" password="itarator" Thanks in advance.

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  • Conditionally set a column to its default value in Postgres

    - by Evgeny
    I've got a PostgreSQL 8.4 table with an auto-incrementing, but nullable, integer column. I want to update some column values and, if this column is NULL then set it to its default value (which would be an integer auto-generated from a sequence), but I want to return its value in either case. So I want something like this: UPDATE mytable SET incident_id = COALESCE(incident_id, DEFAULT), other = 'somethingelse' WHERE ... RETURNING incident_id Unfortunately, this doesn't work - it seems that DEFAULT is special and cannot be part of an expression. What's the best way to do this?

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  • Can I join two tables whereby the joined table is sorted by a certain column?

    - by Ferdy
    I'm not much of a database guru so I need some help on a query I'm working on. In my photo community project I want to richly visualize tags by not only showing the tag name and counter (# of images inside them), I also want to show a thumb of the most popular image inside the tag (most karma). The table setup is as follow: Image table holds basic image metadata, important is the karma field Imagefile table holds multiple entries per image, one for each format Tag table holds tag definitions Tag_map table maps tags to images In my usual trial and error query authoring I have come this far: SELECT * FROM (SELECT tag.name, tag.id, COUNT(tag_map.tag_id) as cnt FROM tag INNER JOIN tag_map ON (tag.id = tag_map.tag_id) INNER JOIN image ON tag_map.image_id = image.id INNER JOIN imagefile on image.id = imagefile.image_id WHERE imagefile.type = 'smallthumb' GROUP BY tag.name ORDER BY cnt DESC) as T1 WHERE cnt > 0 ORDER BY cnt DESC [column clause of inner query snipped for the sake of simplicity] This query gives me somewhat what I need. The outer query makes sure that only tags are returned for which there is at least 1 image. The inner query returns the tag details, such as its name, count (# of images) and the thumb. In addition, I can sort the inner query as I want (by most images, alphabetically, most recent, etc) So far so good. The problem however is that this query does not match the most popular image (most karma) of the tag, it seems to always take the most recent one in the tag. How can I make sure that the most popular image is matched with the tag?

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  • Better way to do SELECT with GROUP BY

    - by Luca Romagnoli
    Hi i've wrote a query that works: SELECT `comments`.* FROM `comments` RIGHT JOIN (SELECT MAX( id ) AS id, core_id, topic_id FROM comments GROUP BY core_id, topic_id order by id desc) comm ON comm.id = comments.id LIMIT 10 I want know if it is possible (and how) to rewrite it to get better performance. Thanks

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  • Help with a MySQL SELECT WHERE Clause

    - by Dr. DOT
    A column in my table contains email addresses. I have a text string that contains the a few usernames of email addresses separated by commas. I can make text sting into an array if necessary to get my SELECT WHERE clause to work correctly. Text string search argument is 'bob,sally,steve' I want to produce a WHERE clause that only returns rows where the username portion of the email address in the table matches one of the usernames in my text string search argument. Thus a row with [email protected] would not be returned but [email protected] would be. Does anyone have a WHERE clause sample that produces this result? Thanks.

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  • Should I catch exceptions thrown when closing java.sql.Connection

    - by jb
    Connection.close() may throw SqlException, but I have always assumed that it is safe to ignore any such exceptions (and I have never seen code that does not ignore them). Normally I would write: try{ connection.close(); }catch(Exception e) {} Or try{ connection.close(); }catch(Exception e) { logger.log(e.getMessage(), e); } The question is: Is it bad practice (and has anyone had problems when ignoring such exeptions). When Connection.close() does throw any exception. If it is bad how should I handle the exception. Comment: I know that discarding exceptions is evil, but I'm reffering only to exceptions thrown when closing a connection (and as I've seen this is fairly common in this case). Does anyone know when Connection.close() may throw anything?

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  • Generating Running Sum of Ratings in SQL

    - by Koobz
    I have a rating table. It boils down to: rating_value created +2 april 3rd -5 april 20th So, every time someone gets rated, I track that rating event in the database. I want to generate a rating history/time graph where the rating is the sum of all ratings up to that point in time on a graph. I.E. A person's rating on April 5th might be select sum(rating_value) from ratings where created <= april 5th The only problem with this approach is I have to run this day by day across the interval I'm interested in. Is there some trick to generating a running total using this sort of data? Otherwise, I'm thinking the best approach is to create a denormalized "rating history" table alongside the individual ratings.

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  • Oracle SQL CMD Line!!!

    - by DAVID
    Hi when ever perform select statements in the command line tool it doesnt use all of the space.. ive modified buffer size and window size and it just doesnt work. here is the Screenshot http://img19.imageshack.us/img19/8954/cmdoracle.jpg

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  • Adding a computed column to an ActiveRecord query

    - by bmwbzz
    Hi, I am running a query using a scope and some conditions. Something like this: conditions[:offset] = (options[:page].to_i - 1) * PAGE_SIZE unless options[:page].blank? conditions[:limit] = options[:limit] ||= PAGE_SIZE scope = Promo.enabled.active results = scope.all conditions I'd like to add a computed column to the query (at the point when I'm now calling scope.all). Something like this: (ACOS(least(1,COS(0.71106459055501)*COS(-1.2915436464758)*COS(RADIANS(addresses.lat))*COS(RADIANS(addresses.lng))+ COS(0.71106459055501)*SIN(-1.2915436464758)*COS(RADIANS(addresses.lat))*SIN(RADIANS(addresses.lng))+ SIN(0.71106459055501)*SIN(RADIANS(addresses.lat))))*3963.19) as accurate_distance Is there a way to do that without just using find_by_sql and rewriting the whole existing query? Thanks!

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