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  • Is SELECT INTO able to affect data from its original table during UPDATE

    - by driveby
    Whilst asking this question asp.net scheduling timed events user murph posted some insightful information: Point about this is that its very, very simple - you have an process for exchange that is performing a clearly defined task and you have a high frequency task that is not doing anything particularly complex, its a straightforward query (select from table where sent = false and send at < value) - probably into temporary table so that you can run a single query update after you've done the sends - that you can optimise the index for. You're not trying to queue up a huge pile of event triggers, just one that fires once a minute and processes things that are due. Is it possible to SELECT data from table X INTO table Y and have the UPDATES that are performed on table Y pushed into table X? I guess the alternative would be that the data gets updated in table Y then an update command can be run on table X based on the data in table Y. What would be the advantage of selecting into another table? Thank you,

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  • Ordering Wordpress posts by most recently commented on

    - by Hardseat
    What's the query to list wordpress posts by most recent, with posts most recently commented on going to the top of the order? (Standard "message board" style) This post looked promising: http://stackoverflow.com/questions/698438/ordering-wordpress-posts-by-most-recent-comment But the query is clearly wrong. Can anyone help?

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  • How to use a data type (table) defined in another database in SQL2k8?

    - by Victor Rodrigues
    I have a Table Type defined in a database. It is used as a table-valued parameter in a stored procedure. I would like to call this procedure from another database, and in order to pass the parameter, I need to reference this defined type. But when I do DECLARE @table dbOtherDatabase.dbo.TypeName , it tells me that The type name 'dbOtherDatabase.dbo.TypeName' contains more than the maximum number of prefixes. The maximum is 1. How could I reference this table type?

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  • Database indexes - what should they be

    - by WebweaverD
    Most of my database tables have a clear unique index through which lookups are done 90% of the time but I am a bit unsure on this one - I have a table which keeps track of user rating totals for items in my database, I now want to add another table, to track individual ratings with an ip address column to make sure no one can rate something twice. Since I can see this becoming a big, high use table it is important to optimize it correctly. (MYSQL table) This table will have the following fields: rating_id(always - unique), item_id (always - not unique), user_id (optional - not unique), ip_address (always - not unique), rating_value(always - not unique), has_review(bool) Now I envisions 90% the queries going something like this: When a user rates something - select where item_id = x and ip_address = y, (if rows = 0) insert rating When in user account pages - select where ip_address = x or username = y Now none of the fields searched on are unique, can I still use them as indexes (for example item _id and ip_address), can I have two indexes and will this still improve performance over a non indexed table?

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  • Query next/previous record

    - by Rob
    I'm trying to find a better way to get the next or previous record from a table. Let's say I have a blog or news table: CREATE TABLE news ( news_id INT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT, news_datestamp DATETIME NOT NULL, news_author VARCHAR(100) NOT NULL, news_title VARCHAR(100) NOT NULL, news_text MEDIUMTEXT NOT NULL ); Now on the frontend I want navigation buttons for the next or previous records, if i'm sorting by news_id, I can do something rather simple like: SELECT MIN(news_id) AS next_news_id FROM news WHERE news_id > '$old_news_id' LIMIT 1 SELECT MAX(news_id) AS prev_news_id FROM news WHERE news_id < '$old_news_id' LIMIT 1 But the news can be sorted by any field, and I don't necessarily know which field is sorted on, so this won't work if the user sorts on news_author for example. I've resorted to the rather ugly and inefficient method of sorting the entire table and looping through all records until I find the record I need. $res = mysql_query("SELECT news_id FROM news ORDER BY `$sort_column` $sort_way"); $found = $prev = $next = 0; while(list($id) = mysql_fetch_row($res)) { if($found) { $next = $id; break; } if($id == $old_news_id) { $found = true; continue; } $prev = $id; } There's got to be a better way.

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  • Syntax for combining joins in mysql

    - by UltraVi01
    I seem to remember reading somewhere that there is a way to combine LEFT JOIN statements into a more simple query. I have the following query and was hoping someone could kindly take a look at it. SET @userId = 8; SELECT ug.user_id, COUNT(DISTINCT goal_id) as matches FROM user_goal ug, user u, profile p LEFT JOIN user_block ub ON @userId = ub.blocked_id LEFT JOIN user_block ub2 ON @userId = ub2.blocker_id LEFT JOIN user_user uu ON @userId = uu.user_id LEFT JOIN friend_request fr ON @userId = fr.user_id WHERE ug.user_id = u.id AND u.profile_id = p.id AND (ub.blocker_id IS NULL OR ub.blocker_id != ug.user_id) AND (ub2.blocked_id IS NULL OR ub2.blocked_id != ug.user_id) AND (uu.user_friends_id IS NULL OR uu.user_friends_id != ug.user_id) AND (fr.to_user_id IS NULL OR (fr.to_user_id != ug.user_id)) AND ug.user_id!=@userId AND p.suggestible AND goal_id IN (SELECT iug.goal_id FROM user_goal iug WHERE user_id=@userId) GROUP BY user_id ORDER BY matches DESC LIMIT 4

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  • How do I Put Several Select Statements into Different Columns

    - by Russ Bradberry
    I basically have 7 select statement that I need to have the results output into separate columns. Normally I would use a crosstab for this but I need a fast efficient way to go about this as there are over 7 billion rows in the table. I am using the vertica database system. Below is an example of my statements: SELECT COUNT(user_id) AS '1' FROM event_log_facts WHERE date_dim_id=20100101 SELECT COUNT(user_id) AS '2' FROM event_log_facts WHERE date_dim_id=20100102 SELECT COUNT(user_id) AS '3' FROM event_log_facts WHERE date_dim_id=20100103 SELECT COUNT(user_id) AS '4' FROM event_log_facts WHERE date_dim_id=20100104 SELECT COUNT(user_id) AS '5' FROM event_log_facts WHERE date_dim_id=20100105 SELECT COUNT(user_id) AS '6' FROM event_log_facts WHERE date_dim_id=20100106 SELECT COUNT(user_id) AS '7' FROM event_log_facts WHERE date_dim_id=20100107

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  • Select proper columns from JOIN statement

    - by Alexander Stalt
    I have two tables: table1, table2. Table1 has 10 columns, table2 has 2 columns. SELECT * FROM table1 AS T1 INNER JOIN table2 AS T2 ON T1.ID = T2.ID I want to select all columns from table1 and only 1 column from table2. Is it possible to do that without enumerating all columns from table1 ?

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  • Access DoCmd.OpenForm Not Working

    - by user961743
    Looking for a second set of eyes to figure out my problem with an Access form filter. I created a search form, when filled in, appends search criteria to a string variable (strQuery) that is put in place to the [WhereCondition] for opening a form. However, when the script is ran, nothing comes up except for a filtered form with no records. Here is the line that opens the form: DoCmd.OpenForm "ADD_NEW_NCMR", , , strQuery Before the line is ran, strQuery equals: 1=1 AND [NCMR].[NCMR_NUM] = '12-129' The form name, and table.column combination are all correct. In fact, using the DCount function returns the result of 1, which is correct for this query, and returns the correct number for other queries as well. This makes me think that there is nothing wrong with the where condition. DCount("[NCMR_NUM]", "NCMR", strQuery)

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  • Linq ChangeConflictException (ASP.NET MVC) - occurs when submitting DataContext changes

    - by Alex
    System.Data.Linq.ChangeConflictException: 2 of X updates failed. at System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at PROJECT.Controllers.HomeController.ClickProc(Int32 id, String code, String n) This is what I get very often. This action is done thousands of times a day, and I get this exception about once every 5 seconds. From what I understand it happens when something changes in the database in the period between creating DataContext and updating it. Am I right? What's the problem here and how can I fix it?

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  • Lua SQL: peeking at cursors

    - by NP
    I am using LuaSQL, and query for a result set using con:execute(sql_stmt), which returns a cursor. How do I see if there is at least one row in that resultset, without doing a cursor:fetch to pop that first row?

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  • Data warehousing in sql server 2008

    - by 3bd
    Hi All: I am new to data warehousing and I am a little confused plz provide some simple steps to create a cube and fill it and make querey on it to know : I have a database with the original data and I have designed the star schema and made appropriate tables I have created an analysis service project in VS 2008 and then I have made the data source -data source view-dimensions - and the cube all that based on the star schema i have created previously now: what should I do to: fill this cube make query on this cube

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  • Fact table with multiple facts

    - by Jeff Meatball Yang
    I have a dimension (SiteItem) has two important facts: perUserClicks perBrowserClicks however, within this dimension, I have groups of dimensions based on an attribute column (let's call the groups AboveFoldItems, LeftNavItems, OnTheFlyItems, etc.) each have more facts that are specific to that group: AboveFoldItems: eyeTime, loadTime LeftNavItems: mouseOverTime OnTheFlyItems: doesn't have any extra, but may in the future Is the following fact table schema ok? DateKey SessionKey SiteItemKey perUserClicks perBrowserClicks eyeTime loadTime mouseOverTime It seems a little wasteful since only some columns pertain to some dimension keys (the irrelevant facts are left NULL). But... this seems like it would be a common problem, so there should be a common solution for this, right?

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  • Should I return IEnumerable<T> or IQueryable<T> from my DAL?

    - by Gary '-'
    I know this could be opinion, but I'm looking for best practices. As I understand, IQueryable implements IEnumerable, so in my DAL, I currently have method signatures like the following: IEnumerable<Product> GetProducts(); IEnumerable<Product> GetProductsByCategory(int cateogoryId); Product GetProduct(int productId); Should I be using IQueryable here? What are the pros and cons of either approach? Note that I am planning on using the Repository pattern so I will have a class like so: public class ProductRepository { DBDataContext db = new DBDataContext(<!-- connection string -->); public IEnumerable<Product> GetProductsNew(int daysOld) { return db.GetProducts() .Where(p => p.AddedDateTime > DateTime.Now.AddDays(-daysOld )); } } Should I change my IEnumerable<T> to IQueryable<T>? What advantages/disadvantages are there to one or the other?

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  • Good strategy for copying a "sliding window" of data from a table?

    - by chiborg
    I have a MySQL table from a third-party application that has millions of rows and only one index - the timestamp of each entry. Now I want to do some heavy self-joins and queries on the data using fields other than the timestamp. Doing the query on the original table would bring the database to a crawl, adding indexes to the table is not an option. Additionally, I only need entries that are newer than one week. My current strategy for doing the queries efficiently is to use a separate table (aux_table) that has the necessary indexes. My questions are: Is there another way to do the queries? and if not, How do I update the data in the indexed table efficiently? So far I have found two approaches for updating aux_table: Truncate aux_table and insert the desired data from the original table. Not very efficient because all the indexes must be re-crated. Check for the biggest timestamp in aux_table and insert all entries with a greater or equal timestamp from the original table. Occasionally drop older entries. Only copying entries with greater timestamp leads to dropped entries (because of entries with same timestamp that were inserted into the original table after the last update).

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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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  • How can I perform this query between related tables without using UNION?

    - by jeremy
    Suppose I have two separate tables that I watch to query. Both of these tables has a relation with a third table. How can I query both tables with a single, non UNION based query? I want the result of the search to rank the results by comparing a field on each table. Here's a theoretical example. I have a User table. That User can have both CDs and books. I want to find all of that user's books and CDs with a single query matching a string ("awesome" in this example). A UNION based query might look like this: SELECT "book" AS model, name, ranking FROM book WHERE name LIKE 'Awesome%' UNION SELECT "cd" AS model, name, ranking FROM cd WHERE name LIKE 'Awesome%' ORDER BY ranking DESC How can I perform a query like this without the UNION? If I do a simple left join from User to Books and CDs, we end up with a total number of results equal to the number of matching cds timse the number of matching books. Is there a GROUP BY or some other way of writing the query to fix this?

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  • Linq with a long where clause

    - by Jeremy Roberts
    Is there a better way to do this? I tried to loop over the partsToChange collection and build up the where clause, but it ANDs them together instead of ORing them. I also don't really want to explicitly do the equality on each item in the partsToChange list. var partsToChange = new Dictionary<string, string> { {"0039", "Vendor A"}, {"0051", "Vendor B"}, {"0061", "Vendor C"}, {"0080", "Vendor D"}, {"0081", "Vendor D"}, {"0086", "Vendor D"}, {"0089", "Vendor E"}, {"0091", "Vendor F"}, {"0163", "Vendor E"}, {"0426", "Vendor B"}, {"1197", "Vendor B"} }; var items = new List<MaterialVendor>(); foreach (var x in partsToChange) { var newItems = ( from m in MaterialVendor where m.Material.PartNumber == x.Key && m.Manufacturer.Name.Contains(x.Value) select m ).ToList(); items.AddRange(newItems); } Additional info: I am working in LINQPad.

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  • How do I convert int? into int

    - by Richard77
    Hello, I've create a SPROC that saves an object and returns the id of the new object saved. Now, I'd like to return an int not an int? public int Save(Contact contact) { int? id; context.Save_And_SendBackID(contact.FirstName, contact.LastName, ref id); //How do I return an int instead of an int? } Thanks for helping

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  • data type mismatch when comparing dates in MS-Access

    - by jonos
    I have dates stored in an MS-Access table in the 'General Date' format. I'm trying to create a query that returns records between a specific date range (all records from March 2010) however I encounter a 'data type mismatch in critera expression' message. Here is my statement; SELECT Loan.loan_datetimeLeant, product_name, [product_artist/director], product_category, loanItem_cost FROM Loan INNER JOIN ((Product INNER JOIN Item ON Product.[product_id] = Item.[product_id]) INNER JOIN Loan_Items ON Item.[item_id] = Loan_Items.[item_id]) ON (Loan.[cust_id] = Loan_Items.[cust_id]) AND (Loan.[loan_datetimeLeant] = Loan_Items.[loan_datetimeLeant]) WHERE Loan.loan_datetimeLeant = '01/03/2010' AND Loan.loan_datetimeLeant <= '31/03/2010' ORDER BY Loan.loan_datetimeLeant ; I have tried variations on the date format (mm/dd/yyyy, dd/mm/yyyy 00:00:00)

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  • Should I use integer primary IDs?

    - by arthurprs
    For example, I always generate an auto-increment field for the users table, but I also specify a UNIQUE index on their usernames. There are situations that I first need to get the userId for a given username and then execute the desired query, or use a JOIN in the desired query. It's 2 trips to the database or a JOIN vs. a varchar index. Should I use integer primary IDs? Is there a real performance benefit on INT over small VARCHAR indexes?

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  • GridView will not update underlying data source

    - by John Christensen
    So I'm been pounding on this problem all day. I've got a LinqDataSource that points to my model and a GridView that consumes it. When I attempt to do an update on the GridView, it does not update the underlying data source. I thought it might have to do with the LinqDataSource, so I added a SqlDataSource and the same thing happens. The aspx is as follows (the code-behind page is empty): <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="Data Source=devsql32;Initial Catalog=Steam;Persist Security Info=True;" ProviderName="System.Data.SqlClient" SelectCommand="SELECT [LangID], [Code], [Name] FROM [Languages]" UpdateCommand="UPDATE [Languages] SET [Code]=@Code WHERE [LangID]=@LangId"> </asp:SqlDataSource> <asp:GridView ID="_languageGridView" runat="server" AllowPaging="True" AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="LangId" DataSourceID="SqlDataSource1"> <Columns> <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" /> <asp:BoundField DataField="LangId" HeaderText="Id" ReadOnly="True" /> <asp:BoundField DataField="Code" HeaderText="Code" /> <asp:BoundField DataField="Name" HeaderText="Name" /> </Columns> </asp:GridView> <asp:LinqDataSource ID="_languageDataSource" ContextTypeName="GeneseeSurvey.SteamDatabaseDataContext" runat="server" TableName="Languages" EnableInsert="True" EnableUpdate="true" EnableDelete="true"> </asp:LinqDataSource> What in the world am I missing here? This problem is driving me insane.

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