Search Results

Search found 6186 results on 248 pages for 'syntax'.

Page 217/248 | < Previous Page | 213 214 215 216 217 218 219 220 221 222 223 224  | Next Page >

  • What does it mean to pass a &variable to a function? E.g., string& insert ( size_t pos1, const strin

    - by Bob Montgomery
    I understand passing a pointer, and returning a pointer: char * strcat ( char * destination, const char * source ); You're passing a variable that contains the address to a char; returning the same. But what does it mean to pass something using the reference operator? Or to return it? string& insert ( size_t pos1, const string& str ); I mean, I understand what actually happens, I just don't understand the notation. Why isn't the notation this instead: string * insert ( size_t pos1, const string * str ); //made up I presume it has something to do with passing/returning the instance of a class, but what? Is this syntax valid; if not why not and if so what does it mean? char & strcat ( char & destination, const char & source ); //made up (all of the function declarations, except the last made-up two, are from http://www.cplusplus.com )

    Read the article

  • What's the best way to get a bunch of rows from MySQL if you have an array of integer primary keys?

    - by Evan P.
    I have a MySQL table with an auto-incremented integer primary key. I want to get a bunch of rows from the table based on an array of integers I have in memory in my program. The array ranges from a handful to about 1000 items. What's the most efficient query syntax to get the rows? I can think of a few: "SELECT * FROM thetable WHERE id IN (1, 2, 3, 4, 5)" (this is what I do now) "SELECT * FROM thetable where id = 1 OR id = 2 OR id = 3" Multiple queries of the form "SELECT * FROM thetable WHERE id = 1". Probably the most friendly to the query cache, but expensive due to having lots of query parsing. A union, like "SELECT * FROM thetable WHERE id = 1 UNION SELECT * FROM thetable WHERE id = 2 ..." I'm not sure if MySQL caches the results of each query; it's also the most verbose format. I think using the NoSQL interface in MySQL 5.6+ would be the most efficient way to do this, but I'm not yet up to MySQL 5.6.

    Read the article

  • Use MySQL trigger to update another table when duplicate key found

    - by Jason
    Been scratching my head on this one, hoping one of you kind people and direct me towards solving this problem. I have a mysql table of customers, it contains a lot of data, but for the purpose of this question, we only need to worry about 4 columns 'ID', 'Firstname', 'Lastname', 'Postcode' Problem is, the table contains a lot of duplicated customers. A new table is being created where each customer is unique and for us, we decide a unique customer is based on 'Firstname', 'Lastname' and 'Postcode' However, (this is the important bit) we need to ensure each new "unique" customer record also can be matched to the original multiple entries of that customer in the original table. I believe the best way to do this is to have a third table, that has 'NewUniqueID', 'OldCustomerID'. So we can search this table for 'NewUniqueID' = '123' and it would return multiple 'OldCustomerID' values where appropriate. I am hoping to make this work using a trigger and the on duplicate key syntax. So what would happen is as follows: An query is run taking the old customer table and inserting it in to the new unique table. (A standard Insert Select query) On duplicate key continue adding records, but add one entry in to the third table noting the 'NewUniqueID' that duped along with the 'OldCustomerID' of the record we were trying to insert. Hope this makes sense, my apologies if it isn't clear. I welcome and appreciate any thoughts on this one! Many thanks Jason

    Read the article

  • c# Why can't open generic types be passed as parameters?

    - by Rich Oliver
    Why can't open generic types be passed as parameters. I frequently have classes like: public class Example<T> where T: BaseClass { public int a {get; set;} public List<T> mylist {get; set;} } Lets say BaseClass is as follows; public BaseClass { public int num; } I then want a method of say: public int MyArbitarySumMethod(Example example)//This won't compile Example not closed { int sum = 0; foreach(BaseClass i in example.myList)//myList being infered as an IEnumerable sum += i.num; sum = sum * example.a; return sum; } I then have to write an interface just to pass this one class as a parameter as follows: public interface IExample { public int a {get; set;} public IEnumerable<BaseClass> myIEnum {get;} } The generic class then has to be modified to: public class Example<T>: IExample where T: BaseClass { public int a {get; set;} public List<T> mylist {get; set;} public IEnumerable<BaseClass> myIEnum {get {return myList;} } } That's a lot of ceremony for what I would have thought the compiler could infer. Even if something can't be changed I find it psychologically very helpful if I know the reasons / justifications for the absence of Syntax short cuts.

    Read the article

  • Change a finder method w/ parameters to an association

    - by Sai Emrys
    How do I turn this into a has_one association? (Possibly has_one + a named scope for size.) class User < ActiveRecord::Base has_many :assets, :foreign_key => 'creator_id' def avatar_asset size = :thumb # The LIKE is because it might be a .jpg, .png, or .gif. # More efficient methods that can handle that are OK. ;) self.assets.find :first, :conditions => ["thumbnail = '#{size}' and filename LIKE ?", self.login + "_#{size}.%"] end end EDIT: Cuing from AnalogHole on Freenode #rubyonrails, we can do this: has_many :assets, :foreign_key => 'creator_id' do def avatar size = :thumb find :first, :conditions => ["thumbnail = ? and filename LIKE ?", size.to_s, proxy_owner.login + "_#{size}.%"] end end ... which is fairly cool, and makes syntax a bit better at least. However, this still doesn't behave as well as I would like. Particularly, it doesn't allow for further nice find chaining (such that it doesn't execute this find until it's gotten all its conditions). More importantly, it doesn't allow for use in an :include. Ideally I want to do something like this: PostsController def show post = Post.get_cache(params[:id]) { Post.find(params[:id], :include => {:comments => {:users => {:avatar_asset => :thumb}} } ... end ... so that I can cache the assets together with the post. Or cache them at all, really - e.g. get_cache(user_id){User.find(user_id, :include => :avatar_assets)} would be a good first pass. This doesn't actually work (self == User), but is correct in spirit: has_many :avatar_assets, :foreign_key => 'creator_id', :class_name => 'Asset', :conditions => ["filename LIKE ?", self.login + "_%"] (Also posted on Refactor My Code.)

    Read the article

  • Manifesto for Integrated Development Environments

    - by Hugo S Ferreira
    Have you recently take a peek at Coda, or Espresso, or Textmate? Or even Google Chrome's Developer Tools? They are well designed, intuitive, interface rich, and extensible. But Coda, Espresso or Textmate, among several, are text editors, not IDEs. On the other side, VIM and Emacs live in the last century, and Eclipse is an overbloated platform. This is more like an outcry for a decent, common infrastructure for REAL IDEs. But there's some questions attached: (i) what features are needed for such a product and (ii) what products are out there that could fullfil this need, and what are they missing. So here's my draft for a manifesto: Manifesto for Integrated Development Environments: We favor interactivity and productivity over syntax and tools. We favor inline, contextual documentation over man and html files. We favor high-definition, graphic-capable color screens over 80x25 character terminals. We favor the use of advanced input schemas over unintuitive keyboard shortcuts. We favor a common, extensible and customizable infrastructure over unmaintained chaintools. We know the difference between search&replace and refactoring. We know the difference between integrated debugging support over a terminal window. We know the difference between semantic-aware code-completion over dumb textual templates. We favor the usage of standards like (E)BNF.

    Read the article

  • T-SQL Query, combine columns from multiple rows into single column

    - by Shayne
    I have seeen some examples of what I am trying to do using COALESCE and FOR XML (seems like the better solution). I just can't quite get the syntax right. Here is what I have (I will shorten the fields to only the key ones): Table Fields ------ ------------------------------- Requisition ID, Number IssuedPO ID, Number Job ID, Number Job_Activity ID, JobID (fkey) RequisitionItems ID, RequisitionID(fkey), IssuedPOID(fkey), Job_ActivityID (fkey) I need a query that will list ONE Requisition per line with its associated Jobs and IssuedPOs. (The requisition number start with "R-" and the Job Number start with "J-"). Example: R-123 | "PO1; PO2; PO3" | "J-12345; J-6780" Sure thing Adam! Here is a query that returns multiple rows. I have to use outer joins, since not all Requisitions have RequisitionItems that are assigned to Jobs and/or IssuedPOs (in that case their fkey IDs would just be null of course). SELECT DISTINCT Requisition.Number, IssuedPO.Number, Job.Number FROM Requisition INNER JOIN RequisitionItem on RequisitionItem.RequisitionID = Requisition.ID LEFT OUTER JOIN Job_Activity on RequisitionItem.JobActivityID = Job_Activity.ID LEFT OUTER JOIN Job on Job_Activity.JobID = Job.ID LEFT OUTER JOIN IssuedPO on RequisitionItem.IssuedPOID = IssuedPO.ID

    Read the article

  • Numerical calculations in Prolog

    - by user8472
    While reading SICP I came across logic programming chapter 4.4. Then I started looking into the Prolog programming language and tried to understand some simple assignments in Prolog. I found that Prolog seems to have troubles with numerical calculations. Here is the computation of a factorial in standard Prolog: f(0, 1). f(A, B) :- A > 0, C is A-1, f(C, D), B is A*D. The issues I find is that I need to introduce two auxiliary variables (C and D), a new syntax (is) and that the problem is non-reversible (i.e., f(5,X) works as expected, but f(X,120) does not). Naively, I expect that at the very least C is A-1, f(C, D) above may be replaced by f(A-1,D), but even that does not work. My question is: Why do I need to do this extra "stuff" in numerical calculations but not in other queries? I do understand (and SICP is quite clear about it) that in general information on "what to do" is insufficient to answer the question of "how to do it". So the declarative knowledge in (at least some) math problems is insufficient to actually solve these problems. But that begs the next question: How does this extra "stuff" in Prolog help me to restrict the formulation to just those problems where "what to do" is sufficient to answer "how to do it"?

    Read the article

  • Web development tool that can comprehend the concept of more than one language in a file at once

    - by thecoshman
    I currently use notepad++ on windows or gedit on ubuntu. Both of them work great with code highlighting and hinting etc. But both of them suffer from a huge flaw. I am yet to find a code editor that can handle this concept: <?php // ooh, look I am doing some php ?><a onclick="alert('hay, some javascript in here now!')"> This link is HTML?!</a> <?PHP echo("NOW we have some php as well!"); ?> At the moment, I just have to settle for the one language. I want something that can think of a that text as a default as HTML, but notice when sections are PHP. I want those sections of PHP to have there own code hinting and highlighting. Even more, lets say in an 'if else' I exit PHP, write some HTML then back into PHP, I want it to work out how the braces ( '{' and '}' ) should match up and let me know if I have missed one. I want the sections of in-line JavaScript to be picked up as such. I want all of these languages to get checked for syntax! Damn it, I want to tool that understands more than one language at once!

    Read the article

  • Square Brackets in Python Regular Expressions (re.sub)

    - by user1479984
    I'm migrating wiki pages from the FlexWiki engine to the FOSwiki engine using Python regular expressions to handle the differences between the two engines' markup languages. The FlexWiki markup and the FOSwiki markup, for reference. Most of the conversion works very well, except when I try to convert the renamed links. Both wikis support renamed links in their markup. For example, Flexwiki uses: "Link To Wikipedia":[http://www.wikipedia.org/] FOSwiki uses: [[http://www.wikipedia.org/][Link To Wikipedia]] both of which produce something that looks like I'm using the regular expression renameLink = re.compile ("\"(?P<linkName>[^\"]+)\":\[(?P<linkTarget>[^\[\]]+)\]") to parse out the link elements from the FlexWiki markup, which after running through something like "Link Name":[LinkTarget] is reliably producing groups <linkName> = Link Name <linkTarget = LinkTarget My issue occurs when I try to use re.sub to insert the parsed content into the FOSwiki markup. My experience with regular expressions isn't anything to write home about, but I'm under the impression that, given the groups <linkName> = Link Name <linkTarget = LinkTarget a line like line = renameLink.sub ( "[[\g<linkTarget>][\g<linkName>]]" , line ) should produce [[LinkTarget][Link Name]] However, in the output to the text files I'm getting [[LinkTarget [[Link Name]] which breaks the renamed links. After a little bit of fiddling I managed a workaround, where line = renameLink.sub ( "[[\g<linkTarget>][ [\g<linkName>]]" , line ) produces [[LinkTarget][ [[Link Name]] which, when displayed in FOSwiki looks like <[[Link Name> <--- Which WORKS, but isn't very pretty. I've also tried line = renameLink.sub ( "[[\g<linkTarget>]" + "[\g<linkName>]]" , line ) which is producing [[linkTarget [[linkName]] There are probably thousands of instances of these renamed links in the pages I'm trying to convert, so fixing it by hand isn't any good. For the record I've run the script under Python 2.5.4 and Python 2.7.3, and gotten the same results. Am I missing something really obvious with the syntax? Or is there an easy workaround?

    Read the article

  • searching for multiple columns mysql and php

    - by addi
    i'm trying to search for multiple columns using this code: <?php // Connection Database $search = $_POST ['Search']; mysql_connect("xxxxxx", "xxxxxx", "xxxxx") or die ("Error Connecting to Database"); mysql_select_db("xxxxx") or die('Error'); $data = mysql_query("SELECT CourseName, CourseDescription, CourseLeader FROM course MATCH (CourseName, CourseDescription, CourseLeader) AGAINST ('". $search ."') or die('Error'); Print "<table border cellpadding=3>"; while($info = mysql_fetch_array( $data )) { Print "<tr>"; Print "<th>Course Name:</th> <td>".$info['CourseName'] . "</td> "; Print "<th>Course Description:</th><td>".$info['CourseDescription'] . "</td> "; Print "<th>Course Leader:</th><td>".$info['CourseLeader'] . " </td></tr>"; } Print "</table>"; ?> i'm getting the following error: Parse error: syntax error, unexpected T_STRING in /home/a7105766/public_html/website/scripts/coursesearchdb.php on line 30 what am I doing wrong?? cheers

    Read the article

  • Passing in extra parameters in a URL

    - by Scott Atkinson
    I have the below column on my table what gets binded on pageload, the parameters in there work fine but i need to add an additional parameter which is the fullname which is the next column along but im having trouble figuring our the syntax, here is my ASP <asp:TemplateField HeaderText="ID"> <ItemTemplate> <asp:HyperLink ID="hyperLeadID" runat="server" NavigateUrl='<%#Eval("ID","/documents/Q-Sheet.aspx?LeadID={0}&isHappyCallReferral=yes&isHappyName={1}") %>' Text='<%#Eval("ID")%>'></asp:HyperLink> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Referral Name"> <ItemTemplate> <asp:Label ID="lblRefName" CssClass="gvItem" runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.Name") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> As you can see at the end of ID column i have added isHappyName={1} which i assumed it would select the next column along as it starts at 0 but it keeps throwing an error which is "Index (zero based) must be greater than or equal to zero and less than the size of the argument list." Can someone help me to pass the usersname through the URL Thanks

    Read the article

  • How can I send GET data to multiple URLs at the same time using cURL?

    - by Rob
    My apologies, I've actually asked this question multiple times, but never quite understood the answers. Here is my current code: while($resultSet = mysql_fetch_array($SQL)){ $ch = curl_init($resultSet['url'] . $fullcurl); //load the urls and send GET data curl_setopt($ch, CURLOPT_TIMEOUT, 2); //Only load it for two seconds (Long enough to send the data) curl_exec($ch); //Execute the cURL curl_close($ch); //Close it off } //end while loop What I'm doing here, is taking URLs from a MySQL Database ($resultSet['url']), appending some extra variables to it, just some GET data ($fullcurl), and simply requesting the pages. This starts the script running on those pages, and that's all that this script needs to do, is start those scripts. It doesn't need to return any output. Just the load the page long enough for the script to start. However, currently it's loading each URL (currently 11) one at a time. I need to load all of them simultaneously. I understand I need to use curl_multi_*, but I haven't the slightest idea on how cURL functions work, so I don't know how to change my code to use curl_multi_* in a while loop. So my questions are: How can I change this code to load all of the URLs simultaneously? Please explain it and not just give me code. I want to know what each individual function does exactly. Will curl_multi_exec even work in a while loop, since the while loop is just sending each row one at a time? And of course, any references, guides, tutorials about cURL functions would be nice, as well. Preferably not so much from php.net, as while it does a good job of giving me the syntax, its just a little dry and not so good with the explanations.

    Read the article

  • T-SQL: how to sort table rows based on 2 columns

    - by Criss Nautilus
    I'm quite stuck with this problem for sometime now.. How do I sort column A depending on the contents of Column B? I have this sample: ID count columnA ColumnB 12 1 A B 13 2 C D 14 3 B C I want to sort it like this: ID count ColumnA ColumnB 12 1 A B 14 3 B C 13 2 C D so I need to sort the rows if the previous row of ColumnB = the next row of ColumnA I'm thinking a loop? but can't quite imagine how it will work... I was thinking it will go like this (maybe) SELECT a.ID, a.ColumnA, a.ColumnB FROM TableA WITH a (NOLOCK) LEFT JOIN TableA b WITH (NOLOCK) ON a.ID = b.ID and a.counts = b.counts Where a.columnB = b.ColumnA the above code isn't working though and I was thinking more on the lines of... DECLARE @counts int = 1 DECLARE @done int = 0 --WHILE @done = 0 BEGIN SELECT a.ID, a.ColumnA, a.ColumnB FROM TableA WITH a (NOLOCK) LEFT JOIN TableA b WITH (NOLOCK) ON a.ID = b.ID and a.counts = @counts Where a.columnB = b.ColumnA set @count = @count +1 END If this was a C code, would be easier for me but t-sql's syntax is making it a bit harder for a noobie like me.

    Read the article

  • Find and Replace with Notepad++

    - by Levi
    I have a document that was converted from PDF to HTML for use on a company website to be referenced and indexed for search. I'm attempting to format the converted document to meet my needs and in doing so I am attempting to clean up some of the junk that was pulled over from when it was a PDF such as page numbers, headers, and footers. luckily all of these lines that need to be removed are in blocks of 4 lines unfortunately they are not exactly the same therefore cannot be removed with a simple literal replace. The lines contain numbers which are incremental as they correlate with the pages. How can I remove the following example from my html file. Title<br> 10<br> <hr> <A name=11></a>Footer<br> I've tried many different regular expression attempts but as my skill in that area is limited I can't find the proper syntax. I'm sure i'm missing something fairly easy as it would seem all I need is a wildcard replace for the two numbers in the code and the rest is literal. any help is apprciated

    Read the article

  • How to write to a Text File in Pipe delimited format from MS Sql Server / ASP.Net?

    - by NJTechGuy
    I have a text file which needs to be constantly updated (regular intervals). All I want is the syntax and possibly some code that outputs data from a MS Sql Database using ASP.Net. The code I have so far is : <%@ Import Namespace="System.IO" %> <script language="vb" runat="server"> sub Page_Load(sender as Object, e as EventArgs) Dim FILENAME as String = Server.MapPath("Output.txt") Dim objStreamWriter as StreamWriter ' If Len(Dir$(FILENAME)) > 0 Then Kill(FILENAME) objStreamWriter = File.AppendText(FILENAME) objStreamWriter.WriteLine("A user viewed this demo at: " & DateTime.Now.ToString()) objStreamWriter.Close() Dim objStreamReader as StreamReader objStreamReader = File.OpenText(FILENAME) Dim contents as String = objStreamReader.ReadToEnd() lblNicerOutput.Text = contents.Replace(vbCrLf, "<br>") objStreamReader.Close() end sub </script> <asp:label runat="server" id="lblNicerOutput" Font-Name="Verdana" /> With PHP, it is a breeze, but with .Net I have no clue. If you could help me with the database connectivity and how to write the data in pipe delimited format to an Output.txt file, that had be awesome. Thanks guys!

    Read the article

  • Calling a non-activeX DLL in a VB6 application in Vista/Win7

    - by user1490330
    I have a VB6 app that utilizes a non-activeX DLL (non-registering). It's declared via the classic Public Declare Function "Function Name" Lib "Library.DLL" syntax. On my dev machine (XP) it works fine but when I deploy to Vista or Win7 I'm constantly greeted with a Run Time Error 48 - File Not Found for the DLL in question. I have tried copying that DLL to every directory I can think of including every environment path on the test machine and the app path too. These are all 32-bit test environments so it's not a SysWow64 issue. Possibly throwing a wrench into the mix is the fact that the application in question is an Outlook COM Addin. I managed to install VB6 on Win7 and was able to run a tiny sample app that utilizes this DLL (outside of the Outlook process) so I know it works PROVIDED the DLL is located in App path. If I call App.Path from my DLL when I run it on the test environment it shows, to no surprise, my installation directory however the DLL is there. I tried turning off UAC. I tried making the App.Path directory permissions open to everyone, still no dice.

    Read the article

  • MySQL Update query with left join and group by

    - by Rob
    I am trying to create an update query and making little progress in getting the right syntax. The following query is working: SELECT t.Index1, t.Index2, COUNT( m.EventType ) FROM Table t LEFT JOIN MEvents m ON (m.Index1 = t.Index1 AND m.Index2 = t.Index2 AND (m.EventType = 'A' OR m.EventType = 'B') ) WHERE (t.SpecialEventCount IS NULL) GROUP BY t.Index1, t.Index2 It creates a list of triplets Index1,Index2,EventCounts. It only does this for case where t.SpecialEventCount is NULL. The update query I am trying to write should set this SpecialEventCount to that count, i.e. COUNT(m.EventType) in the query above. This number could be 0 or any positive number (hence the left join). Index1 and Index2 together are unique in Table t and they are used to identify events in MEvent. How do I have to modify the select query to become an update query? I.e. something like UPDATE Table SET SpecialEventCount=COUNT(m.EventType)..... but I am confused what to put where and have failed with numerous different guesses.

    Read the article

  • LINQ - Querying a list filtered via a Many-to-Many reltionship

    - by user118190
    Please excuse the context of my question for I did not know how to exactly word it. To not complicate things further, here's my business requirement: "bring me back all the Employees where they belong in Department "X". So when I view this, it will display all of the Employees that belong to this Department. Here's my environment: Silverlight 3 with Entity Framework 1.0 and WCF Data Services 1.0. I am able to load and bind all kinds of lists (simple), no problem. I don't feel that my environment matters and that's why I feel it is a LINQ question more than the technologies. My question is for scenarios where I have 3 tables linked, i.e. entities (collections). For example, I have this in my EDM: Employee--EmployeeProject--Project. Here's the table design from the Database: Employee (table1) ------------- EmployeeID (PK) FirstName other Attributes ... EmployeeProject (table2) ------------- EmployeeProjectID (PK) EmployeeID (FK) ProjectID (FK) AssignedDate other Attributes ... Project (table3) ------------- ProjectID (PK) Name other Attributes ... Here's the EDM design from Entity Framework: ------------------------ Employee (entity1) ------------------------ (Scalar Properties) ------------------- EmployeeID (PK) FirstName other Attributes ... ------------------- (Navigation Properties) ------------------- EmployeeProjects ------------------------ EmployeeProject (entity2) ------------------------ (Scalar Properties) ------------------- EmployeeProjectID (PK) AssignedDate other Attributes ... ------------------- (Navigation Properties) ------------------- Employee Project ------------------------ Project (entity3) ------------------------ (Scalar Properties) ------------------- ProjectID (PK) Name other Attributes ... ------------------- (Navigation Properties) ------------------- EmployeeProjects So far, I have only been able to do: var filteredList = Context.Employees .Where(e => e.EmployeeProjects.Where(ep => ep.Project.Name == "ProjectX")) NOTE: I have updated the syntax of the query after John's post. As you can see, I can only query, the related entity (EmployeeProjects). All I want is being able to filter to Project from the Employee entity. Thanks for any advice.

    Read the article

  • PostgreSQL storing paths for reference in scripts

    - by Brian D.
    I'm trying to find the appropriate place to store a system path in PostgreSQL. What I'm trying to do is load values into a table using the COPY command. However, since I will be referring to the same file path regularly I want to store that path in one place. I've tried creating a function to return the appropriate path, but I get a syntax error when I call the function in the COPY command. I'm not sure if this is the right way to go about it, but I'll post my code anyway. COPY command: COPY employee_scheduler.countries (code, name) FROM get_csv_path('countries.csv') WITH CSV; Function Definition: CREATE OR REPLACE FUNCTION employee_scheduler.get_csv_path(IN file_name VARCHAR(50)) RETURNS VARCHAR(250) AS $$ DECLARE path VARCHAR(200) := E'C:\\Brian\\Work\\employee_scheduler\\database\\csv\\'; file_path VARCHAR(250) := ''; BEGIN file_path := path || file_name; RETURN file_path; END; $$ LANGUAGE plpgsql; If anyone has a different idea on how to accomplish this I'm open to suggestions. Thanks for any help!

    Read the article

  • MySQL query puzzle - finding what WOULD have been the most recent date

    - by Hank
    I've looked all over and haven't yet found an intelligent way to handle this, though I feel sure one is possible: One table of historical data has quarterly information: CREATE TABLE Quarterly ( unique_ID INT UNSIGNED NOT NULL, date_posted DATE NOT NULL, datasource TINYINT UNSIGNED NOT NULL, data FLOAT NOT NULL, PRIMARY KEY (unique_ID)); Another table of historical data (which is very large) contains daily information: CREATE TABLE Daily ( unique_ID INT UNSIGNED NOT NULL, date_posted DATE NOT NULL, datasource TINYINT UNSIGNED NOT NULL, data FLOAT NOT NULL, qtr_ID INT UNSIGNED, PRIMARY KEY (unique_ID)); The qtr_ID field is not part of the feed of daily data that populated the database - instead, I need to retroactively populate the qtr_ID field in the Daily table with the Quarterly.unique_ID row ID, using what would have been the most recent quarterly data on that Daily.date_posted for that data source. For example, if the quarterly data is 101 2009-03-31 1 4.5 102 2009-06-30 1 4.4 103 2009-03-31 2 7.6 104 2009-06-30 2 7.7 105 2009-09-30 1 4.7 and the daily data is 1001 2009-07-14 1 3.5 ?? 1002 2009-07-15 1 3.4 && 1003 2009-07-14 2 2.3 ^^ then we would want the ?? qtr_ID field to be assigned '102' as the most recent quarter for that data source on that date, and && would also be '102', and ^^ would be '104'. The challenges include that both tables (particularly the daily table) are actually very large, they can't be normalized to get rid of the repetitive dates or otherwise optimized, and for certain daily entries there is no preceding quarterly entry. I have tried a variety of joins, using datediff (where the challenge is finding the minimum value of datediff greater than zero), and other attempts but nothing is working for me - usually my syntax is breaking somewhere. Any ideas welcome - I'll execute any basic ideas or concepts and report back.

    Read the article

  • Beginner SQL section: avoiding repeated expression

    - by polygenelubricants
    I'm entirely new at SQL, but let's say that on the StackExchange Data Explorer, I just want to list the top 15 users by reputation, and I wrote something like this: SELECT TOP 15 DisplayName, Id, Reputation, Reputation/1000 As RepInK FROM Users WHERE RepInK > 10 ORDER BY Reputation DESC Currently this gives an Error: Invalid column name 'RepInK', which makes sense, I think, because RepInK is not a column in Users. I can easily fix this by saying WHERE Reputation/1000 > 10, essentially repeating the formula. So the questions are: Can I actually use the RepInK "column" in the WHERE clause? Do I perhaps need to create a virtual table/view with this column, and then do a SELECT/WHERE query on it? Can I name an expression, e.g. Reputation/1000, so I only have to repeat the names in a few places instead of the formula? What do you call this? A substitution macro? A function? A stored procedure? Is there an SQL quicksheet, glossary of terms, language specification, anything I can use to quickly pick up the syntax and semantics of the language? I understand that there are different "flavors"?

    Read the article

  • HQL query problem

    - by yigit
    Hi all, I'm using this hql query for my filters. Query perfectly working except width (string) part. Here is the query, public IList<ColorGroup> GetDistinctColorGroups(int typeID, int finishID, string width) { string queryStr = "Select distinct c from ColorGroup c inner join c.Products p " + "where p.ShowOnline = 1 "; if (typeID > 0) queryStr += " and p.ProductType.ID = " + typeID; if (finishID > 0) queryStr += " and p.FinishGroup.ID = " + finishID; if (width != "") queryStr += " and p.Size.Width = " + width; IList<ColorGroup> colors = NHibernateSession.CreateQuery(queryStr).List<ColorGroup>(); return colors; } ProductType and Size have same mappings and relations. This is the error; NHibernate.QueryException: illegal syntax near collection: Size [Select distinct c from .Domain.ColorGroup c inner join c.Products p where p.ShowOnline = 1 and p.ProductType.ID = 1 and p.FinishGroup.ID = 5 and p.Size.Width = 4] Any ideas ?

    Read the article

  • Using list() to extract a data.table inside of a function

    - by Nathan VanHoudnos
    I must admit that the data.table J syntax confuses me. I am attempting to use list() to extract a subset of a data.table as a data.table object as described in Section 1.4 of the data.table FAQ, but I can't get this behavior to work inside of a function. An example: require(data.table) ## Setup some test data set.seed(1) test.data <- data.table( X = rnorm(10), Y = rnorm(10), Z = rnorm(10) ) setkey(test.data, X) ## Notice that I can subset the data table easily with literal names test.data[, list(X,Y)] ## X Y ## 1: -0.8356286 -0.62124058 ## 2: -0.8204684 -0.04493361 ## 3: -0.6264538 1.51178117 ## 4: -0.3053884 0.59390132 ## 5: 0.1836433 0.38984324 ## 6: 0.3295078 1.12493092 ## 7: 0.4874291 -0.01619026 ## 8: 0.5757814 0.82122120 ## 9: 0.7383247 0.94383621 ## 10: 1.5952808 -2.21469989 I can even write a function that will return a column of the data.table as a vector when passed the name of a column as a character vector: get.a.vector <- function( my.dt, my.column ) { ## Step 1: Convert my.column to an expression column.exp <- parse(text=my.column) ## Step 2: Return the vector return( my.dt[, eval(column.exp)] ) } get.a.vector( test.data, 'X') ## [1] -0.8356286 -0.8204684 -0.6264538 -0.3053884 0.1836433 0.3295078 ## [7] 0.4874291 0.5757814 0.7383247 1.5952808 But I cannot pull a similar trick for list(). The inline comments are the output from the interactive browser() session. get.a.dt <- function( my.dt, my.column ) { ## Step 1: Convert my.column to an expression column.exp <- parse(text=my.column) ## Step 2: Enter the browser to play around browser() ## Step 3: Verity that a literal X works: my.dt[, list(X)] ## << not shown >> ## Step 4: Attempt to evaluate the parsed experssion my.dt[, list( eval(column.exp)] ## Error in `rownames<-`(`*tmp*`, value = paste(format(rn, right = TRUE), (from data.table.example.R@1032mCJ#7) : ## length of 'dimnames' [1] not equal to array extent return( my.dt[, list(eval(column.exp))] ) } get.a.dt( test.data, "X" ) What am I missing? Update: Due to some confusion as to why I would want to do this I wanted to clarify. My use case is when I need to access a data.table column when when I generate the name. Something like this: set.seed(2) test.data[, X.1 := rnorm(10)] which.column <- 'X' new.column <- paste(which.column, '.1', sep="") get.a.dt( test.data, new.column ) Hopefully that helps.

    Read the article

  • How do I insert null fields with Perl's DBD::Pg?

    - by User1
    I have a Perl script inserting data into Postgres according to a pipe delimited text file. Sometimes, a field is null (as expected). However, Perl makes this field into an empty string and the Postgres insert statement fails. Here's a snippet of code: use DBI; #Connect to the database. $dbh=DBI-connect('dbi:Pg:dbname=mydb','mydb','mydb',{AutoCommit=1,RaiseError=1,PrintError=1}); #Prepare an insert. $sth=$dbh-prepare("INSERT INTO mytable (field0,field1) SELECT ?,?"); while (<){ #Remove the whitespace chomp; #Parse the fields. @field=split(/\|/,$_); print "$_\n"; #Do the insert. $sth-execute($field[0],$field[1]); } And if the input is: a|1 b| c|3 EDIT: Use this input instead. a|1|x b||x c|3|x It will fail at b|. DBD::Pg::st execute failed: ERROR: invalid input syntax for integer: "" I just want it to insert a null on field1 instead. Any ideas? EDIT: I simplified the input at the last minute. The old input actually made it work for some reason. So now I changed the input to something that will make the program fail. Also note that field1 is a nullable integer datatype.

    Read the article

< Previous Page | 213 214 215 216 217 218 219 220 221 222 223 224  | Next Page >