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  • Is there a way to give a subquery an alias in Oracle 11g SQL?

    - by Matt Pascoe
    Is there a way to give a subquery in Oracle 11g an alias like: select * from (select client_ref_id, request from some_table where message_type = 1) abc, (select client_ref_id, response from some_table where message_type = 2) defg where abc.client_ref_id = def.client_ref_id; Otherwise is there a way to join the two subqueries based on the client_ref_id. I realize there is a self join, but on the database I am running on a self join can take up to 5 min to complete (there is some extra logic in the actual query I am running but I have determined the self join is what is causing the issue). The individual subqueries only take a few seconds to complete by them selves. The self join query looks something like: select st.request, st1.request from some_table st, some_table st1 where st.client_ref_id = st1.client_ref_id;

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  • Puzzle: find the minimum number of weights

    - by avd
    I came across this question: say given two weights 1 and 3, u can weigh 1,2 (by 3-1),3,4 (by 3+1). Now find the minimum number of weights so that you can measure 1 to 1000. So the answer was 1,3,9,27... I want to know how do you arrive at such a solution means powers of 3. What is the thought process? Source: http://classic-puzzles.blogspot.com/search/label/Google%20Interview%20Puzzles Solution: http://classic-puzzles.blogspot.com/2006/12/solution-to-shopkeeper-problem.html

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  • How do I translate a List<string> into a SqlParameter for a Sql In statement?

    - by KallDrexx
    I seem to be confused on how to perform an In statement with a SqlParameter. So far I have the following code: cmd.CommandText = "Select dscr from system_settings where setting in @settings"; cmd.Connection = conn; cmd.Parameters.Add(new SqlParameter("@settings", settingList)); reader = cmd.ExecuteReader(); settingsList is a List<string>. When cmd.ExecuteReader() is called, I get an ArgumentException due to not being able to map a List<string> to "a known provider type". How do I (safely) perform an In query with SqlCommands?

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  • In SQL / MySQL, what is the difference between "On" and "Where" in a join statement?

    - by Jian Lin
    The following statements give the same result (one is using "on", and the other using "where"): mysql> select * from gifts INNER JOIN sentGifts on gifts.giftID = sentGifts.giftID; mysql> select * from gifts INNER JOIN sentGifts where gifts.giftID = sentGifts.giftID; I can only see in a case of a Left Outer Join finding the "unmatched" cases: (to find out the gifts that were never sent by anybody) mysql> select name from gifts LEFT OUTER JOIN sentgifts on gifts.giftID = sentgifts.giftID where sentgifts.giftID IS NULL; In this case, it is first using "on", and then "where". Does the "on" first do the matching, and then "where" does the "secondary" filtering? Or is there a more general rule of using "on" versus "where"? Thanks.

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  • find a duplicate entry in an array in constant space and O(n) time [closed]

    - by Anubhav Agarwal
    Possible Duplicate: Algorithm to find a duplicate entry in constant space and O(n) time Given an array of N integer such that only one integer is repeated. Find the repeated integer in O(n) time and constant space. There is no range for the value of integers or the value of N For example given an array of 6 integers as 23 45 67 87 23 47. The answer is 23 (I hope this covers ambiguous and vague part) I searched on the net but was unable to find any such question in which range of integers was not fixed. Also here is an example that answers a similar question to mine but here he created a hash table with the highest integer value in C++.But the cpp does not allow such to create an array with 2^64 element(on a 64-bit computer).

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  • One-way flight trip problem.

    - by psihodelia
    You are going on a one-way indirect flight trip that includes billions transfers. You are not stopping twice in the same airport. You have 1 ticket for each part of your trip. Each ticket contains src and dst airport. All the tickets you have are randomly sorted. You forgot the original departure airport (very first src) and your destination (last dst). Design an algorithm to reconstruct your trip with minimum big-O complexity.

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  • Bug in Programming Interviews Exposed?

    - by Sam
    Hi, I could not find an errata for the 2nd edition of this book. My question concerns the if-statement in the following piece of code. void removeHead (Node ** head) { Node * temp; if (!(*head)) { temp = (*head)->next; delete *head; *head = temp; } } So I understand that the point of the if-statement is to check if the Node is null. However by adding an additional "!" to the evaluation, wouldn't this negate the false value of null? Would it be correct to change it to something like: if (*head) { ... } Also if anyone knows where I can find an official errata for the 2nd edition that would be great. Thanks, Sam

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  • Integrated Windows authentication in IIS causing ADO.NET failure

    - by TrueWill
    We have a .NET 3.5 Web Service running under IIS. It must use identity impersonate="true" and Integrated Windows authentication in order to authenticate to third-party software. In addition, it connects to a SQL Server database using ADO.NET and SQL Server Authentication (specifying a fixed User ID and Password in the connection string). Everything worked fine until the database was moved to another SQL Server. Then the Web Service would throw the following exception: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) This error only occurs if identity impersonate is true in the Web.config. Again, the connection string hasn't changed and it specifies the user. I have tested the connection string and it works, both under the impersonated account and under the service account (and from both the remote machine and the server). What needs to be changed to get this to work with impersonation?

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  • How to compute palindrome from a stream of characters in sub-linear space/time?

    - by wrick
    I don't even know if a solution exists or not. Here is the problem in detail. You are a program that is accepting an infinitely long stream of characters (for simplicity you can assume characters are either 1 or 0). At any point, I can stop the stream (let's say after N characters were passed through) and ask you if the string received so far is a palindrome or not. How can you do this using less sub-linear space and/or time.

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  • Is there a way to give a subquery an alias in Oracle 10g SQL?

    - by Matt Pascoe
    Is there a way to give a subquery in Oracle 11g an alias like: select * from (select client_ref_id, request from some_table where message_type = 1) abc, (select client_ref_id, response from some_table where message_type = 2) defg where abc.client_ref_id = def.client_ref_id; Otherwise is there a way to join the two subqueries based on the client_ref_id. I realize there is a self join, but on the database I am running on a self join can take up to 5 min to complete (there is some extra logic in the actual query I am running but I have determined the self join is what is causing the issue). The individual subqueries only take a few seconds to complete by them selves. The self join query looks something like: select st.request, st1.request from some_table st, some_table st1 where st.client_ref_id = st1.client_ref_id;

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  • SQL - How to display the students with the same age?

    - by Cristian
    the code I wrote only tells me how many students have the same age. I want their names too... SELECT YEAR(CURRENT DATE-DATEOFBIRTH) AS AGE, COUNT(*) AS HOWMANY FROM STUDENTS GROUP BY YEAR(CURRENT DATE-DATEOFBIRTH); this returns something like this: AGE HOWMANY --- ------- 21 3 30 5 Thank you. TABLE STUDENTS COLUMNS: StudentID (primary key), Name(varchar), Firstname(varchar), Dateofbirth(varchar) I was thinking of maybe using the code above and somewhere add the function concat that will put the stundents' names on the same row as in

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  • t-sql - find differences for pk's in a single table (Self join?)

    - by Pace
    Hi Experts, My situation is this. I have a table of products with a pk "Parent" which has "Components" The data looks something like this Parent(PK) Component Car1 Wheel Car1 Tyre Car1 Roof Car2 Alloy Car2 Tyre Car2 Roof Car3 Alloy Car3 Tyre Car3 Roof Car3 Leather Seats Now what I want to do is some query that I can feed two codes in and see the differences... IE If I feed in "Car1", "Car2" it would return something like; Parent Component Car1 Wheel Car2 Alloy As this is the difference between the two. If I said "Car1", "Car3" I would expect; Parent Component Car1 Wheel Car3 Alloy Car3 Leather Seats Your help with this matter would be greatly appreciated.

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  • How to find validity of a string of parentheses, curly brackets and square brackets?

    - by Rajendra
    I recently came in contact with this interesting problem. You are given a string containing just the characters '(', ')', '{', '}', '[' and ']', for example, "[{()}]", you need to write a function which will check validity of such an input string, function may be like this: bool isValid(char* s); these brackets have to close in the correct order, for example "()" and "()[]{}" are all valid but "(]", "([)]" and "{{{{" are not! I came out with following O(n) time and O(n) space complexity solution, which works fine: Maintain a stack of characters. Whenever you find opening braces '(', '{' OR '[' push it on the stack. Whenever you find closing braces ')', '}' OR ']' , check if top of stack is corresponding opening bracket, if yes, then pop the stack, else break the loop and return false. Repeat steps 2 - 3 until end of the string. This works, but can we optimize it for space, may be constant extra space, I understand that time complexity cannot be less than O(n) as we have to look at every character. So my question is can we solve this problem in O(1) space?

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  • How to change a primary key in SQL to auto_increment?

    - by Jian Lin
    I have a table in MySQL that has a primary key: mysql> desc gifts; +---------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------------+-------------+------+-----+---------+-------+ | giftID | int(11) | NO | PRI | NULL | | | name | varchar(80) | YES | | NULL | | | filename | varchar(80) | YES | | NULL | | | effectiveTime | datetime | YES | | NULL | | +---------------+-------------+------+-----+---------+-------+ but I wanted to make it auto_increment. The following statement failed. How can it be modified so that it can work? thanks mysql> alter table gifts modify giftID int primary key auto_increment; ERROR 1068 (42000): Multiple primary key defined

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  • SQL Server 2008 vs 2005 udf xml perfomance problem.

    - by user344495
    Ok we have a simple udf that takes a XML integer list and returns a table: CREATE FUNCTION [dbo].[udfParseXmlListOfInt] ( @ItemListXml XML (dbo.xsdListOfInteger) ) RETURNS TABLE AS RETURN ( --- parses the XML and returns it as an int table --- SELECT ListItems.ID.value('.','INT') AS KeyValue FROM @ItemListXml.nodes('//list/item') AS ListItems(ID) ) In a stored procedure we create a temp table using this UDF INSERT INTO @JobTable (JobNumber, JobSchedID, JobBatID, StoreID, CustID, CustDivID, BatchStartDate, BatchEndDate, UnavailableFrom) SELECT JOB.JobNumber, JOB.JobSchedID, ISNULL(JOB.JobBatID,0), STO.StoreID, STO.CustID, ISNULL(STO.CustDivID,0), AVL.StartDate, AVL.EndDate, ISNULL(AVL.StartDate, DATEADD(day, -8, GETDATE())) FROM dbo.udfParseXmlListOfInt(@JobNumberList) TMP INNER JOIN dbo.JobSchedule JOB ON (JOB.JobNumber = TMP.KeyValue) INNER JOIN dbo.Store STO ON (STO.StoreID = JOB.StoreID) INNER JOIN dbo.JobSchedEvent EVT ON (EVT.JobSchedID = JOB.JobSchedID AND EVT.IsPrimary = 1) LEFT OUTER JOIN dbo.Availability AVL ON (AVL.AvailTypID = 5 AND AVL.RowID = JOB.JobBatID) ORDER BY JOB.JobSchedID; For a simple list of 10 JobNumbers in SQL2005 this returns in less than 1 second, in 2008 this run against the exact same data returns in 7 min. This is on a much faster machine with more memory. Any ideas?

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  • Can I make an identity field span multiple tables in SQL Server?

    - by johnnycakes
    Can I have an "identity" (unique, non-repeating) column span multiple tables? For example, let's say I have two tables: Books and Authors. Authors AuthorID AuthorName Books BookID BookTitle The BookID column and the AuthorID column are identity columns. I want the identity part to span both columns. So, if there is an AuthorID with a value of 123, then there cannot be a BookID with a value of 123. And vice versa. I hope that makes sense. Is this possible? Thanks. Why do I want to do this? I am writing an APS.NET MVC app. I am creating a comment section. Authors can have comments. Books can have comments. I want to be able to pass an entity ID (a book ID or an author ID) to an action and have the action pull up all the corresponding comments. The action won't care if it's a book or an author or whatever. Sound reasonable?

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  • SQL Server pivots? some way to set column names to values within a row

    - by ccsimpson3
    I am building a system of multiple trackers that are going to use a lot of the same columns so there is a table for the trackers, the tracker columns, then a cross reference for which columns go with which tracker, when a user inserts a tracker row the different column values are stored in multiple rows that share the same record id and store both the value and the name of the particular column. I need to find a way to dynamically change the column name of the value to be the column name that is stored in the same row. i.e. id | value | name ------------------ 23 | red | color 23 | fast | speed needs to look like this. id | color | speed ------------------ 23 | red | fast Any help is greatly appreciated, thank you.

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  • How to use LINQ to SQL to create ranked search results?

    - by quakkels
    I am looking for a way to use l2s to return ranked result based on keywords. I would like to take a keyword and be able to search the table for that keyword using .contains(). The trick that I haven't been able to figure out is how to get a count of how many times that keyqord appears, and then .OrderByDescending() based on that count. So if i had some thing like: string keyword = "SomeKeyword"; IQueryable<Article> searchResults = from a in GenesisRepository.Article where a.Body.Contains(keyword) select a; What is the best way to order searchResults based on the number of times keyword appears in a.Body? Thanks for any help.

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  • Where should my "filtering" logic reside with Linq-2-SQL and ASP.NET-MVC in View or Controller?

    - by Nate Bross
    I have a main Table, with several "child" tables. TableA and TableAChild1 and TableAChild2. I have a view which shows the information in TableA, and then has two columns of all items in TableAChild1 and TableAChild2 respectivly, they are rendered with Partial views. Both child tables have a bit field for VisibleToAll, and depending on user role, I'd like to either display all related rows, or related rows where VisibleToAll = true. This code, feels like it should be in the controller, but I'm not sure how it would look, because as it stands, the controller (limmited version) looks like this: return View("TableADetailView", repos.GetTableA(id)); Would something like this be even work, and would it be bad what if my DataContext gets submitted, would that delete all the rows that have VisibleToAll == false? var tblA = repos.GetTableA(id); tblA.TableAChild1 = tblA.TableAChild1.Where(tmp => tmp.VisibleToAll == true); tblA.TableAChild2 = tblA.TableAChild2.Where(tmp => tmp.VisibleToAll == true); return View("TableADetailView", tblA); It would also be simple to add that logic to the RendarPartial call from the main view: <% Html.RenderPartial("TableAChild1", Model.TableAChild1.Where(tmp => tmp.VisibleToAll == true); %>

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