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  • PostgreSQL - select only when specific multiple apperance in column

    - by Horse SMith
    I'm using PostgreSQL. I have a table with 3 fields person, recipe and ingredient person = creator of the recipe recipe = the recipe ingredient = one of the ingredients in the recipe I want to create a query which results in every person who whenever has added carrot to a recipe, the person must also have added salt to the same recipe. More than one person can have created the recipe, in which case the person who added the ingredient will be credited for adding the ingredient. Sometimes the ingredient is used more than once, even by the same person. If this the table: person1, rec1, carrot person1, rec1, salt person1, rec1, salt person1, rec2, salt person1, rec2, pepper person2, rec1, carrot person2, rec1, salt person2, rec2, carrot person2, rec2, pepper person3, rec1, sugar person3, rec1, carrot Then I want this result: person1 Because this person is the only one who whenever has added carrot also have added salt.

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  • In mysql, is "explain ..." always safe?

    - by tye
    If I allow a group of users to submit "explain $whatever" to mysql (via Perl's DBI using DBD::mysql), is there anything that a user could put into $whatever that would make any database changes, leak non-trivial information, or even cause significant database load? If so, how? I know that via "explain $whatever" one can figure out what tables / columns exist (you have to guess names, though) and roughly how many records are in a table or how many records have a particular value for an indexed field. I don't expect one to be able to get any information about the contents of unindexed fields. DBD::mysql should not allow multiple statements so I don't expect it to be possible to run any query (just explain one query). Even subqueries should not be executed, just explained. But I'm not a mysql expert and there are surely features of mysql that I'm not even aware of. In trying to come up with a query plan, might the optimizer actual execute an expression in order to come up with the value that an indexed field is going to be compared against? explain select * from atable where class = somefunction(...) where atable.class is indexed and not unique and class='unused' would find no records but class='common' would find a million records. Might 'explain' evaluate somefunction(...)? And then could somefunction(...) be written such that it modifies data?

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  • Writing a query to find MAX number in PL/SQL

    - by user2461116
    I am suppose to Write a query that will display the largest number of movies rented by one member and that member's name. Give the output column a meaningful name such as MAXIMUM NUMBER. This is what I have. select max(maximum_movies) from (select count(*)maximum_movies from mm_member join mm_rental on mm_rental.member_id = mm_member.member_id group by first, last); I got the maximum number but the output should be like this. First Last Maximum_movies John Doe 4 But the output is Maximum_movies 4 Any suggestions?

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  • Porting Oracle Date Manipulation

    - by Grasper
    I need to port this following from Oracle syntax to Postgresql. Both FLO_END_DT and FLO_START_DATE are of type DATE in Oracle, and TIMESTAMP WITHOUT TIME ZONE in Postgresql: SELECT TRUNC( TO_CHAR(ROUND(( FL.FLO_END_DT- FL.FLO_START_DT)* 24), '9999D99'),2) FROM FLOWS FL I am not familiar enough with Oracle to know what it is trying to accomplish. Any ideas?

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  • How to map combinations of things to a relational database?

    - by Space_C0wb0y
    I have a table whose records represent certain objects. For the sake of simplicity I am going to assume that the table only has one row, and that is the unique ObjectId. Now I need a way to store combinations of objects from that table. The combinations have to be unique, but can be of arbitrary length. For example, if I have the ObjectIds 1,2,3,4 I want to store the following combinations: {1,2}, {1,3,4}, {2,4}, {1,2,3,4} The ordering is not necessary. My current implementation is to have a table Combinations that maps ObjectIds to CombinationIds. So every combination receives a unique Id: ObjectId | CombinationId ------------------------ 1 | 1 2 | 1 1 | 2 3 | 2 4 | 2 This is the mapping for the first two combinations of the example above. The problem is, that the query for finding the CombinationId of a specific Combination seems to be very complex. The two main usage scenarios for this table will be to iterate over all combinations, and the retrieve a specific combination. The table will be created once and never be updated. I am using SQLite through JDBC. Is there any simpler way or a best practice to implement such a mapping?

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  • User has many computers, computers have many attributes in different tables, best way to JOIN?

    - by krismeld
    I have a table for users: USERS: ID | NAME | ---------------- 1 | JOHN | 2 | STEVE | a table for computers: COMPUTERS: ID | USER_ID | ------------------ 13 | 1 | 14 | 1 | a table for processors: PROCESSORS: ID | NAME | --------------------------- 27 | PROCESSOR TYPE 1 | 28 | PROCESSOR TYPE 2 | and a table for harddrives: HARDDRIVES: ID | NAME | ---------------------------| 35 | HARDDRIVE TYPE 25 | 36 | HARDDRIVE TYPE 90 | Each computer can have many attributes from the different attributes tables (processors, harddrives etc), so I have intersection tables like this, to link the attributes to the computers: COMPUTER_PROCESSORS: C_ID | P_ID | --------------| 13 | 27 | 13 | 28 | 14 | 27 | COMPUTER_HARDDRIVES: C_ID | H_ID | --------------| 13 | 35 | So user JOHN, with id 1 owns computer 13 and 14. Computer 13 has processor 27 and 28, and computer 13 has harddrive 35. Computer 14 has processor 27 and no harddrive. Given a user's id, I would like to retrieve a list of that user's computers with each computers attributes. I have figured out a query that gives me a somewhat of a result: SELECT computers.id, processors.id AS p_id, processors.name AS p_name, harddrives.id AS h_id, harddrives.name AS h_name, FROM computers JOIN computer_processors ON (computer_processors.c_id = computers.id) JOIN processors ON (processors.id = computer_processors.p_id) JOIN computer_harddrives ON (computer_harddrives.c_id = computers.id) JOIN harddrives ON (harddrives.id = computer_harddrives.h_id) WHERE computers.user_id = 1 Result: ID | P_ID | P_NAME | H_ID | H_NAME | ----------------------------------------------------------- 13 | 27 | PROCESSOR TYPE 1 | 35 | HARDDRIVE TYPE 25 | 13 | 28 | PROCESSOR TYPE 2 | 35 | HARDDRIVE TYPE 25 | But this has several problems... Computer 14 doesnt show up, because it has no harddrive. Can I somehow make an OUTER JOIN to make sure that all computers show up, even if there a some attributes they don't have? Computer 13 shows up twice, with the same harddrive listet for both. When more attributes are added to a computer (like 3 blocks of ram), the number of rows returned for that computer gets pretty big, and it makes it had to sort the result out in application code. Can I somehow make a query, that groups the two returned rows together? Or a query that returns NULL in the h_name column in the second row, so that all values returned are unique? EDIT: What I would like to return is something like this: ID | P_ID | P_NAME | H_ID | H_NAME | ----------------------------------------------------------- 13 | 27 | PROCESSOR TYPE 1 | 35 | HARDDRIVE TYPE 25 | 13 | 28 | PROCESSOR TYPE 2 | 35 | NULL | 14 | 27 | PROCESSOR TYPE 1 | NULL | NULL | Or whatever result that make it easy to turn it into an array like this [13] => [P_NAME] => [0] => PROCESSOR TYPE 1 [1] => PROCESSOR TYPE 2 [H_NAME] => [0] => HARDDRIVE TYPE 25 [14] => [P_NAME] => [0] => PROCESSOR TYPE 1

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  • sql count conditions

    - by user1311030
    there! I have this question, hope you guys can help me out. So i have this table with two fields: type and authorization in type i have 2 different values: Raid and Hold in authorization i have 2 different values: Accepted or Denied I need to make a view that returns values like this: TYPE:RAID ACCEPTED:5 DENIED:7 Basically i need to know how many of the values in TYPE are Raid, and then how many of them are Accepted and Denied. Thank you in advance!!

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  • Designing a table to store EXIF data

    - by rafale
    I'm looking to get the best performance out of querying a table containing EXIF data. The queries in question will only search the EXIF data for the specified strings and return the row index on a match. With that said, would it better to store the EXIF data in a table with separate columns for each of the tags, or would storing all of the tags in a single column as one long delimited string suit me just as well? There are around 115 EXIF tags I'll be storing, and each record would be around 1500 to 2000 chars in length if concatenated into a single string.

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  • iBatis how to solve a more complex N+1 problem

    - by Alvin
    I have a database that is similar to the following: create table Store(storeId) create table Staff(storeId_fk, staff_id, staffName) create table Item(storeId_fk, itme_id, itemName) The Store table is large. And I have create the following java bean public class Store { List<Staff> myStaff List<Item> myItem .... } public class Staff { ... } public class Item { ... } My question is how can I use iBatis's result map to EFFICIENTLY map from the tables to the java object? I tried: <resultMap id="storemap" class="my.example.Store"> <result property="myStaff" resultMap="staffMap"/> <result property="myItem" result="itemMap"/> </resultMap> (other maps omitted) But it's way too slow since the Store table is VERY VERY large. I tried to follow the example in Clinton's developer guide for the N+1 solution, but I cannot warp my mind around how to use the "groupBy" for an object with 2 list... Any help is appreciated!

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  • acts-as-taggable-on: find tags with name LIKE, sort by tag_counts?

    - by James
    Hi I'm using the rails plugin acts-as-taggable-onand I'm trying to find the top 5 most used tags whose names match and partially match a given query. When I do User.skill_counts.order('count DESC').limit(5).where('name LIKE ?', params[:query]) This return the following error: ActiveRecord::StatementInvalid: SQLite3::SQLException: ambiguous column name: name: SELECT tags.*, COUNT(*) AS count FROM "tags" INNER JOIN users ON users.id = taggings.taggable_id LEFT OUTER JOIN taggings ON tags.id = taggings.tag_id AND taggings.context = 'skills' WHERE (taggings.taggable_type = 'User') AND (taggings.taggable_id IN(SELECT users.id FROM "users")) AND (name LIKE 'asd') GROUP BY tags.id, tags.name HAVING COUNT(*) > 0 ORDER BY count DESC LIMIT 5 But when I do User.skill_counts.first.name this returns "alliteration" I'd appreciate any help on this matter.

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  • HQl equivalent of sql query

    - by kash
    String SQL_QUERY = "SELECT count(*) FROM (SELECT * FROM Url as U where U.pageType=" + 1 + " group by U.pageId having count(U.pageId) = 1)"; query = session.createQuery(SQL_QUERY); I am getting an error org.hibernate.hql.ast.QuerySyntaxException: unexpected token: ( near line 1, column 23 [ SELECT count() FROM (SELECT * FROM Url as U where U.pageType = 2 group by U.pageId having count(U.pageId) = 1)]

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  • Compare values in serialized column in Doctrine with Query Builder

    - by ReynierPM
    I'm building a FormType for a Symfony2 project but I need some Query Builder on the field since I need to compare some values with the one stored on DB and show the results. This is what I have: .... ->add('servicio', 'entity', array( 'mapped' => false, 'class' => 'ComunBundle:TipoServicio', 'property' => 'nombre', 'required' => true, 'label' => false, 'expanded' => true, 'multiple' => true, 'query_builder' => function (EntityRepository $er) { return $er->createQueryBuilder('ts') ->where('ts.tipo_usuario = (:tipo)') ->setParameter('tipo', 1); } )) .... But tipo_usuario at DB table is stored as serialized text for example: record1: value1 | a:1:{i:0;s:1:"1";} record2: value2 | a:4:{i:0;s:1:"1";i:1;s:1:"2";i:2;s:1:"3";i:3;s:1:"4";} I'll have two different forms (I don't know how to pass the Request to a form) in the first one I'll only show the first record and for the second one the first and second record for example: First form will show: checkbox: value1 Second form will show: checkbox: value1 checkbox: value2 I achieve this? Any help?

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  • Error in computed Field of select Query

    - by Shehzad Bilal
    This Query is giving me an error of #1054 - Unknown column 'totalamount' in 'where clause' SELECT (amount1 + amount2) as totalamount FROM `Donation` WHERE totalamount > 1000 I know i can resolve this error by using group by clause and replace my where condition with having clause. But is there any other solution beside using having clause. If group by is the only solution then I want to know why I have to use group by clause even I havent use any aggregate function thanks.

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  • association of more than one model to a listview

    - by Veer
    I have 3 Tables in my database. Each table has 3 fields each, excluding the ID field. out of which 2 fields are of type nvarchar. None of the tables are related. My ListView in the application helps the user to search my database, the search being incremental. The search includes the nvarchar fields of the 3 tables ie, 6 fields in total. Eg: PhoneBook: Name, PhoneNo Notes: Title, Content Bookmarks: Name, url I've the models generated for the 3 tables. Now the ListBox should display the Ph.Name, Title and the Bo.Name fields. ie, It should be bound to them. But they are from different models. I also should be able to perform CRUD operation on the item searched. How would i do that? P.S: Separate ViewModels are created for each Model which are used for their respective views for handling those tables individually. But this is an integrated view where the user should be able to search everything. Also please somebody suggest me a better Title for this question:)

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  • Cannot resolve the collation conflict ???

    - by HAJJAJ
    hi guys I had this error and i don't know how to fix it Message=Cannot resolve the collation conflict between "Arabic_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. note: I already change the collation from the database option -- Collation i change it from "Arabic_CI_AS" to "SQL_Latin1_General_CP1_CI_AS" and i am still getting the same error !! any suggestion to solve this ?

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  • explain these select statements!

    - by user329820
    Hi, I can not get the difference betwwn these statements? would you please help me,I have read some sample of select statements but I did not get these ones. SELECT 'B' FROM T WHERE A = (SELECT NULL); SELECT 'C' FROM T WHERE A = ANY (SELECT NULL); SELECT 'D' FROM T WHERE A = A; I use MySQL

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  • alter mysqldump file before import

    - by julio
    Hi-- I have a mysqldump file created from an earlier version of a product that can't be imported into a new version of the product, since the db structure has changed slightly (mainly altering a column that was NOT NULL DEFAULT 0 to UNIQUE KEY DEFAULT NULL). If I just import the old dump file, it will error out since the column that has default values of 0 now breaks the UNIQUE constraint. It would be easy enough to either manually alter the mysqldump file, or import into a temp table and change it, then copy to the new table. However, is there a way to do this programatically, so it will be repeatable and not manual? (this will need to happen for many instances of this product). I'm thinking something like disabling key constraints for the import, then setting all values that = 0 to NULL, then re-enabling the key constraints? Is this possible? Any help appreciated.

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  • Speed up a web service for auto complete and avoid too many method calls.

    - by jphenow
    So I've got my jquery autocomplete 'working,' but its a little fidgety since I call the webservice method each time a keydown() fires so I get lots of methods hanging and sometimes to get the "auto" to work I have to type it out and backspace a bit because i'm assuming it got its return value a little slow. I've limited the query results to 8 to mininmize time. Is there anything i can do to make this a little snappier? This thing seems near useless if I don't get it a little more responsive. javascript $("#clientAutoNames").keydown(function () { $.ajax({ type: "POST", url: "WebService.asmx/LoadData", data: "{'input':" + JSON.stringify($("#clientAutoNames").val()) + "}", contentType: "application/json; charset=utf-8", dataType: "json", success: function (data) { if (data.d != null) { var serviceScript = data.d; } $("#autoNames").html(serviceScript); $('#clientAutoNames').autocomplete({ minLength: 2, source: autoNames, delay: 100, focus: function (event, ui) { $('#project').val(ui.item.label); return false; }, select: function (event, ui) { $('#clientAutoNames').val(ui.item.label); $('#projectid').val(ui.item.value); $('#project-description').html(ui.item.desc); pkey = $('#project-id').val; return false; } }) .data("autocomplete")._renderItem = function (ul, item) { return $("<li></li>") .data("item.autocomplete", item) .append("<a>" + item.label + "<br>" + item.desc + "</a>") .appendTo(ul); } } }); }); WebService.asmx <WebMethod()> _ Public Function LoadData(ByVal input As String) As String Dim result As String = "<script>var autoNames = [" Dim sqlOut As Data.SqlClient.SqlDataReader Dim connstring As String = *Datasource* Dim strSql As String = "SELECT TOP 2 * FROM v_Clients WHERE (SearchName Like '" + input + "%') ORDER BY SearchName" Dim cnn As Data.SqlClient.SqlConnection = New Data.SqlClient.SqlConnection(connstring) Dim cmd As Data.SqlClient.SqlCommand = New Data.SqlClient.SqlCommand(strSql, cnn) cnn.Open() sqlOut = cmd.ExecuteReader() Dim c As Integer = 0 While sqlOut.Read() result = result + "{" result = result + "value: '" + sqlOut("ContactID").ToString() + "'," result = result + "label: '" + sqlOut("SearchName").ToString() + "'," 'result = result + "desc: '" + title + " from " + company + "'," result = result + "}," End While result = result + "];</script>" sqlOut.Close() cnn.Close() Return result End Function I'm sure I'm just going about this slightly wrong or not doing a better balance of calls or something. Greatly appreciated!

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  • How do I find the user that has both a cat and a dog?

    - by brad
    I want to do a search across 2 tables that have a many-to-one relationship, eg class User << ActiveRecord::Base has_many :pets end class Pet << ActiveRecord::Base belongs_to :users end Now let's say I have some data like so users id name 1 Bob 2 Joe 3 Brian pets id user_id animal 1 1 cat 2 1 dog 3 2 cat 4 3 dog What I want to do is create an active record query that will return a user that has both a cat and a dog (i.e. user 1 - Bob). My attempt at this so far is User.joins(:pets).where('pets.animal = ? AND pets.animal = ?','dog','cat') Now I understand why this doesn't work - it's looking for a pet that is both a dog and a cat so returns nothing. I don't know how to modify this to give me the answer I want however. Does anyone have any suggestions? This seems like it should be easy - it doesn't seem like an especially unusual situation.

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