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  • MySQL GROUP BY with three tables

    - by Psaniko
    I have the following tables: posts (post_id, content, etc) comments (comment_id, post_id, content, etc) posts_categories (post_category_id, post_id, category_id) and this query: SELECT `p`.*, COUNT(comments.comment_id) AS cmts, posts_categories.*,comments.* FROM `posts` AS `p` LEFT JOIN `posts_categories` ON `p`.post_id = `posts_categories`.post_id LEFT JOIN `comments` ON `p`.post_id = `comments`.post_id GROUP BY `p`.`post_id` There are three comments on post_id=1 and four in total. In posts_categories there are two rows, both assigned to post_id=1. I have four rows in posts. But if I query the statement above I get a result of 6 for COUNT(comments.comment_id) at post_id=1. How is this possible? I guess the mistake is somewhere in the GROUP BY clause but I can't figure out where. Any suggestions?

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  • How to select random image of specific size using Django / Python?

    - by Jonathan
    I've been using this little snippet to select random images. However I would like to change it to select only images of a certain size. I'm running into trouble checking against image size. If I use get_image_dimensions() I need to use a conditional statement, which then requires that I allow exceptions. So, I guess I need some pointers on just limiting by image dimensions. Thanks. import os import random import posixpath from django import template from django.conf import settings register = template.Library() def is_image_file(filename): """Does `filename` appear to be an image file?""" img_types = [".jpg", ".jpeg", ".png", ".gif"] ext = os.path.splitext(filename)[1] return ext in img_types @register.simple_tag def random_image(path): """ Select a random image file from the provided directory and return its href. `path` should be relative to MEDIA_ROOT. Usage: <img src='{% random_image "images/whatever/" %}'> """ fullpath = os.path.join(settings.MEDIA_ROOT, path) filenames = [f for f in os.listdir(fullpath) if is_image_file(f)] pick = random.choice(filenames) return posixpath.join(settings.MEDIA_URL, path, pick)

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  • How to map one class against multiple tables with SQLAlchemy?

    - by tote
    Lets say that I have a database structure with three tables that look like this: items - item_id - item_handle attributes - attribute_id - attribute_name item_attributes - item_attribute_id - item_id - attribute_id - attribute_value I would like to be able to do this in SQLAlchemy: item = Item('item1') item.foo = 'bar' session.add(item) session.commit() item1 = session.query(Item).filter_by(handle='item1').one() print item1.foo # => 'bar' I'm new to SQLAlchemy and I found this in the documentation (http://www.sqlalchemy.org/docs/05/mappers.html#mapping-a-class-against-multiple-tables): j = join(items, item_attributes, items.c.item_id == item_attributes.c.item_id). \ join(attributes, item_attributes.c.attribute_id == attributes.c.attribute_id) mapper(Item, j, properties={ 'item_id': [items.c.item_id, item_attributes.c.item_id], 'attribute_id': [item_attributes.c.attribute_id, attributes.c.attribute_id], }) It only adds item_id and attribute_id to Item and its not possible to add attributes to Item object. Is what I'm trying to achieve possible with SQLAlchemy? Is there a better way to structure the database to get the same behaviour of "dynamic columns"?

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  • [MySQL] Optimize Query

    - by bordeux
    Hello. I have problem with optimize this query: SET @SEARCH = "dokumentalne"; SELECT SQL_NO_CACHE `AA`.`version` AS `Version` , `AA`.`contents` AS `Contents` , `AA`.`idarticle` AS `AdressInSQL` , `AA` .`topic` AS `Topic` , MATCH (`AA`.`topic` , `AA`.`contents`) AGAINST (@SEARCH) AS `Relevance` , `IA`.`url` AS `URL` FROM `xv_article` AS `AA` INNER JOIN `xv_articleindex` AS `IA` ON ( `AA`.`idarticle` = `IA`.`adressinsql` ) INNER JOIN ( SELECT `idarticle` , MAX( `version` ) AS `version` FROM `xv_article` WHERE MATCH (`topic` , `contents`) AGAINST (@SEARCH) GROUP BY `idarticle` ) AS `MG` ON ( `AA`.`idarticle` = `MG`.`idarticle` ) WHERE `IA`.`accepted` = "yes" AND `AA`.`version` = `MG`.`version` ORDER BY `Relevance` DESC LIMIT 0 , 30 Now, this query using ^ 20 seconds. How to optimize this? EXPLAIN gives this: 1 PRIMARY AA ALL NULL NULL NULL NULL 11169 Using temporary; Using filesort 1 PRIMARY ALL NULL NULL NULL NULL 681 Using where 1 PRIMARY IA ALL accepted NULL NULL NULL 11967 Using where 2 DERIVED xv_article fulltext topic topic 0 1 Using where; Using temporary; Using filesort This is example server with my data: user: bordeux_4prog password: 4prog phpmyadmin: http://phpmyadmin.bordeux.net/ chive: http://chive.bordeux.net/

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  • AS or not to AS, queries

    - by zeMinimalist
    I'm fairly new to PHP/MySql and using queries in general. I was just wondering if there's any benefit to using "AS" in a query other than trying to make it look cleaner? Does it speed up the query at all? I probably could have figured this out by a google search but I wanted to ask my first question and see how this works. I WILL select an answer (unlike some people...) with: SELECT news.id as id news.name as name FROM news without: SELECT news.id news.name FROM news A more complex example from a many-to-many relationship tutorial I found: SELECT c.name, cf.title FROM celebrities AS c JOIN ( SELECT icf.c_id, icf.f_id, f.title FROM int_cf AS icf JOIN films AS f ON icf.f_id = f.f_id ) AS cf ON c.c_id = cf.c_id ORDER BY c.c_id ASC

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  • .Net Sql Client Provider

    - by sameer
    Have come across a situation where in, if a stored procedure is executed in Query Analyser its execution time is less than a second. But when same Stored Procedure is executed using .NET Sql Client Provide. it is taking 61 seconds. Therefore inorder to troubleshoot this issue we went to SQL Profiler we find the request come to SQL Server less then a second but execution completed after 60 seconds. Can anybody suggest why we have such a deviation. Query is a simple as give below SELECT distinct p1.productID, p1.description FROM Details V INNER JOIN Product P ON V.ProductID=P.ProductID INNER JOIN product p1 on p1.productID=p.parentID WHERE V.MarketID='1159' AND V.FinancialYear='1213' AND V.LEPeriodID= '75' AND p1.parentID=100024 AND p1.statusID = 1 ORDER BY description

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  • Criteria: search for two different entity classes...

    - by RoCMe
    Hi! I have a "super entity" SuperEntity and three entities ChildEntity1, ..., ChildEntity3 which extends the super class. It's easy to search for all entities in the database, i.e. we could use session.createCriteria(SuperEntity.class); It's no problem to search for one specific entity type, too, just replace the SuperEntity with any of the children to look for entities of that type. But I have a problem when allowing 'multiple choice' for the types. I.e., it could be neccessary to search all entities of type 1 and 2, but not of type 3. A first idea was to create two independent queries and join the results in a final list - but that would destroy the paging which uses offset and limit functionality of the database... Is there a possibility in Criteria to join two different queries in one single result list? Kind regards, RoCMe

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  • issue with selecting 1 or 0 in mysql db

    - by jason
    I am having trouble with the following SQL statement i have had this issue before but I cant remember how i fixed the problem, I am guessing the issue with this is that mysql sees 0 as null ? Note I didnt show the first part of the Select statement as its irrelevant my sql works, its showing rows with toffline that are = to 1 as well as 0... FROM table1 AS tb1 LEFT JOIN table2 AS tb2 ON tb2.id = tb1.id2 LEFT JOIN table3 AS tb3 ON tb3.id = tb1.id3 AND tb1.toffline = 0 I have also tried AND NOT tb1.toffline = 1 also WHERE tb1.toffline = 0 all with the same result...

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  • Select products with users

    - by Ploppe
    I have not worked with SQL for quite a long time, and I need some help for a basic query. I have the three following tables: users (id, name) products (id, name) owners (userid, productid, date) One product can be sold by user A to user B and then back to A. Now, I want the list of all products currently owned by every single user with the date of transaction. Currently, my query is this one, but I'm stuck with old data (first association of one product to one user, and not the newest one): SELECT users.name, products.name, date FROM products JOIN owners ON products.id = owners.id JOIN users ON owners.id = user.id GROUP BY product.id Do you have some hints? Thanks

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  • What will or won't cause a thread to block (a question from a test)

    - by fingerprint211b
    I've had a test, and there was a question I lost some points on, because I wasn't able to answer it : Which of the following is NOT a condition which can cause a thread to block : Calling an objects's wait() method Waiting for an I/O operation Calling sleep() Calling yield() Calling join() As far as I know, all of these are blocking calls : wait() returns when an something calls notify(), blocks until then If the thread is WAITING for an I/O operation then it's obviously blocked sleep(), obviously, blocks until the time runs out, or something wakes up the thread yield() "cancels the rest of the thread's timeslice" (lacking a better term), and returns only when the thread is active again join() blocks until the thread it's waiting for terminates. Am I missing something here?

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  • Show the specific field on mysql table based on active date

    - by mrjimoy_05
    Suppose that I have 3 tables: A) Table UsrHeader ----------------- UsrID | UsrName ----------------- 1 | Abc 2 | Bcd B) Table UsrDetail ------------------------------- UsrID | UsrLoc | Date ------------------------------- 1 | LocA | 10 Aug 2012 1 | LocB | 15 Aug 2012 2 | LocA | 10 Aug 2012 C) Table Trx ----------------------------- TrxID | TrxDate | UsrID ----------------------------- 1 | 10 Aug 2012 | 1 2 | 16 Aug 2012 | 1 3 | 11 Aug 2012 | 2 What I want to do is to show the table like: --------------------------------------- TrxID | TrxDate | UsrID | UsrLoc --------------------------------------- 1 | 10 Aug 2012 | 1 | LocA 2 | 16 Aug 2012 | 1 | LocB 3 | 11 Aug 2012 | 2 | LocA Notice that there is one user but different location. That's based on the UsrDetail table that the user on a specified date has moved to another location. So, it should be show the user specific location on that date on every transaction. I have try this code but it is no luck: SELECT trx.TrxID, trx.TrxDate, trx.UsrID, User.UsrName, User.UsrLoc FROM trx INNER JOIN ( SELECT UsrHeader.UsrID, UsrHeader.UsrName, UserDetail.UsrLoc FROM UsrHeader INNER JOIN ( SELECT UsrDetail.UsrID, UsrDetail.UsrLoc, UsrDetail.Date FROM UsrDetail ) AS UserDetail ON UserDetail.UsrID = UsrHeader.UsrID ) AS User ON User.UsrID = trx.UsrID AND trx.TrxDate >= User.Date How to do that? Thanks..

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  • Codeigniter: how do I select count when `$query->num_rows()` doesn't work for me?

    - by mOrloff
    I have a query which is returning a sum, so naturally it returns one row. I need to count the number of records in the DB which made that sum. Here's a sample of the type of query I am talking about (MySQL): SELECT i.id, i.vendor_quote_id, i.product_id_requested, SUM(i.quantity_on_hand) AS qty, COUNT(i.quantity_on_hand) AS count FROM vendor_quote_item AS i JOIN vendor_quote_container AS c ON i.vendor_quote_id = c.id LEFT JOIN company_types ON company_types.company_id = c.company_id WHERE company_types.company_type = 'f' AND i.product_id_requested = 12345678 I have found and am now using the select_min(), select_max(), and select_sum() functions, but my COUNT() is still hard-coded in. The main problem is that I am having to specify the table name in a tightly coupled manner with something like $this->$db->select( 'COUNT(myDbPrefix_vendor_quote_item.quantity_on_hand) AS count' ) which kills portability and makes switching environments a PIA. How can/should I get my the count values I am after with CI in an uncoupled way??

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  • Delete rows out of table that is innerjoined and unioned with 2 others

    - by jonathan
    We have 3 tables (table1, table2, table3), and I need to delete all the rows from table1 that have the same ID in table2 OR table3. To see a list of all of these rows I have this code: ( select table2.ID, table2.name_first, table2.name_last, table2.Collected from table2 inner join table1 on table1.ID = table2.ID where table2.Collected = 'Y' ) union ( select table3.ID, table3.name_first, table3.name_last, table3.Collected from table3 inner join table1 on table1.ID = table3.ID where table3.Collected = 'Y' ) I get back about 200 rows. How do I delete them from table1? I don't have a way to test if my query will work, so I'm nervous about modifying something I found online and potentially deleting data (we do have backups, but I'd rather not test out their integrity). TIA!

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  • No such file or directory python in linux only (coming from windows)

    - by user1804633
    I have the same exact directory structure within a folder in Windows & in Linux (Debian) - where the script is along the static + dataoutput folders How come the following code works fine in Windows, but gives a no such file or directory path error in linux? @app.route('/_getdataoutputfilelisting') def getdataoutputfilelisting(): listoffilesindataouput = getfiles('static/dataoutput') return jsonify(listoffiles = listoffilesindataouput) def getfiles(dirpath): a = [s for s in os.listdir(dirpath) if os.path.isfile(os.path.join(dirpath, s))] a.sort(key=lambda s: os.path.getmtime(os.path.join(dirpath, s))) a.reverse() return a Is there a way to make it universal such that it works in both OSs? Thanks

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  • mysql query for change in values in a logging table

    - by kiasectomondo
    I have a table like this: Index , PersonID , ItemCount , UnixTimeStamp 1 , 1 , 1 , 1296000000 2 , 1 , 2 , 1296000100 3 , 2 , 4 , 1296003230 4 , 2 , 6 , 1296093949 5 , 1 , 0 , 1296093295 Time and index always go up. Its basically a logging table to log the itemcount each time it changes. I get the most recent ItemCount for each Person like this: SELECT * FROM table a INNER JOIN ( SELECT MAX(index) as i FROM table GROUP BY PersonID) b ON a.index = b.i; What I want to do is get get the most recent record for each PersonID that is at least 24 hours older than the most recent record for each Person ID. Then I want to take the difference in ItemCount between these two to get a change in itemcount for each person over the last 24 hours: personID ChangeInItemCountOverAtLeast24Hours 1 3 2 -11 3 6 Im sort of stuck with what to do next. How can I join another itemcount based on latest adjusted timestamp of individual rows?

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  • Reporting Services - It's a Wrap!

    - by smisner
    If you have any experience at all with Reporting Services, you have probably developed a report using the matrix data region. It's handy when you want to generate columns dynamically based on data. If users view a matrix report online, they can scroll horizontally to view all columns and all is well. But if they want to print the report, the experience is completely different and you'll have to decide how you want to handle dynamic columns. By default, when a user prints a matrix report for which the number of columns exceeds the width of the page, Reporting Services determines how many columns can fit on the page and renders one or more separate pages for the additional columns. In this post, I'll explain two techniques for managing dynamic columns. First, I'll show how to use the RepeatRowHeaders property to make it easier to read a report when columns span multiple pages, and then I'll show you how to "wrap" columns so that you can avoid the horizontal page break. Included with this post are the sample RDLs for download. First, let's look at the default behavior of a matrix. A matrix that has too many columns for one printed page (or output to page-based renderer like PDF or Word) will be rendered such that the first page with the row group headers and the inital set of columns, as shown in Figure 1. The second page continues by rendering the next set of columns that can fit on the page, as shown in Figure 2.This pattern continues until all columns are rendered. The problem with the default behavior is that you've lost the context of employee and sales order - the row headers - on the second page. That makes it hard for users to read this report because the layout requires them to flip back and forth between the current page and the first page of the report. You can fix this behavior by finding the RepeatRowHeaders of the tablix report item and changing its value to True. The second (and subsequent pages) of the matrix now look like the image shown in Figure 3. The problem with this approach is that the number of printed pages to flip through is unpredictable when you have a large number of potential columns. What if you want to include all columns on the same page? You can take advantage of the repeating behavior of a tablix and get repeating columns by embedding one tablix inside of another. For this example, I'm using SQL Server 2008 R2 Reporting Services. You can get similar results with SQL Server 2008. (In fact, you could probably do something similar in SQL Server 2005, but I haven't tested it. The steps would be slightly different because you would be working with the old-style matrix as compared to the new-style tablix discussed in this post.) I created a dataset that queries AdventureWorksDW2008 tables: SELECT TOP (100) e.LastName + ', ' + e.FirstName AS EmployeeName, d.FullDateAlternateKey, f.SalesOrderNumber, p.EnglishProductName, sum(SalesAmount) as SalesAmount FROM FactResellerSales AS f INNER JOIN DimProduct AS p ON p.ProductKey = f.ProductKey INNER JOIN DimDate AS d ON d.DateKey = f.OrderDateKey INNER JOIN DimEmployee AS e ON e.EmployeeKey = f.EmployeeKey GROUP BY p.EnglishProductName, d.FullDateAlternateKey, e.LastName + ', ' + e.FirstName, f.SalesOrderNumber ORDER BY EmployeeName, f.SalesOrderNumber, p.EnglishProductName To start the report: Add a matrix to the report body and drag Employee Name to the row header, which also creates a group. Next drag SalesOrderNumber below Employee Name in the Row Groups panel, which creates a second group and a second column in the row header section of the matrix, as shown in Figure 4. Now for some trickiness. Add another column to the row headers. This new column will be associated with the existing EmployeeName group rather than causing BIDS to create a new group. To do this, right-click on the EmployeeName textbox in the bottom row, point to Insert Column, and then click Inside Group-Right. Then add the SalesOrderNumber field to this new column. By doing this, you're creating a report that repeats a set of columns for each EmployeeName/SalesOrderNumber combination that appears in the data. Next, modify the first row group's expression to group on both EmployeeName and SalesOrderNumber. In the Row Groups section, right-click EmployeeName, click Group Properties, click the Add button, and select [SalesOrderNumber]. Now you need to configure the columns to repeat. Rather than use the Columns group of the matrix like you might expect, you're going to use the textbox that belongs to the second group of the tablix as a location for embedding other report items. First, clear out the text that's currently in the third column - SalesOrderNumber - because it's already added as a separate textbox in this report design. Then drag and drop a matrix into that textbox, as shown in Figure 5. Again, you need to do some tricks here to get the appearance and behavior right. We don't really want repeating rows in the embedded matrix, so follow these steps: Click on the Rows label which then displays RowGroup in the Row Groups pane below the report body. Right-click on RowGroup,click Delete Group, and select the option to delete associated rows and columns. As a result, you get a modified matrix which has only a ColumnGroup in it, with a row above a double-dashed line for the column group and a row below the line for the aggregated data. Let's continue: Drag EnglishProductName to the data textbox (below the line). Add a second data row by right-clicking EnglishProductName, pointing to Insert Row, and clicking Below. Add the SalesAmount field to the new data textbox. Now eliminate the column group row without eliminating the group. To do this, right-click the row above the double-dashed line, click Delete Rows, and then select Delete Rows Only in the message box. Now you're ready for the fit and finish phase: Resize the column containing the embedded matrix so that it fits completely. Also, the final column in the matrix is for the column group. You can't delete this column, but you can make it as small as possible. Just click on the matrix to display the row and column handles, and then drag the right edge of the rightmost column to the left to make the column virtually disappear. Next, configure the groups so that the columns of the embedded matrix will wrap. In the Column Groups pane, right-click ColumnGroup1 and click on the expression button (labeled fx) to the right of Group On [EnglishProductName]. Replace the expression with the following: =RowNumber("SalesOrderNumber" ). We use SalesOrderNumber here because that is the name of the group that "contains" the embedded matrix. The next step is to configure the number of columns to display before wrapping. Click any cell in the matrix that is not inside the embedded matrix, and then double-click the second group in the Row Groups pane - SalesOrderNumber. Change the group expression to the following expression: =Ceiling(RowNumber("EmployeeName")/3) The last step is to apply formatting. In my example, I set the SalesAmount textbox's Format property to C2 and also right-aligned the text in both the EnglishProductName and the SalesAmount textboxes. And voila - Figure 6 shows a matrix report with wrapping columns. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Top 31 Favorite Features in Windows Server 2012

    - by KeithMayer
    Over the past month, my fellow IT Pro Technical Evangelists and I have authored a series of articles about our Top 31 Favorite Features in Windows Server 2012.  Now that our series is complete, I’m providing a clickable index below of all of the articles in the series for your convenience, just in case you perhaps missed any of them when they were first released.  Hope you enjoy our Favorite Features in Windows Server 2012! Top 31 Favorite Features in Windows Server 2012 The Cloud OS Platform by Kevin Remde Server Manager in Windows Server 2012 by Brian Lewis Feel the Power of PowerShell 3.0 by Matt Hester Live Migrate Your VMS in One Line of PowerShell by Keith Mayer Windows Server 2012 and Hyper-V Replica by Kevin Remde Right-size IT Budgets with “Storage Spaces” by Keith Mayer Yes, there is an “I” in Team – the NIC Team! by Kevin Remde Hyper-V Network Virtualization by Keith Mayer Get Happy over the FREE Hyper-V Server 2012 by Matt Hester Simplified BranchCache in Windows Server 2012 by Brian Lewis Getting Snippy with PowerShell 3.0 by Matt Hester How to Get Unbelievable Data Deduplication Results by Chris Henley of Veeam Simplified VDI Configuration and Management by Brian Lewis Taming the New Task Manager by Keith Mayer Improve File Server Resiliency with ReFS by Keith Mayer Simplified DirectAccess by Sumeeth Evans SMB 3.0 – The Glue in Windows Server 2012 by Matt Hester Continuously Available File Shares by Steven Murawski of Edgenet Server Core - Improved Taste, Less Filling, More Uptime by Keith Mayer Extend Your Hyper-V Virtual Switch by Kevin Remde To NIC or to Not NIC Hardware Requirements by Brian Lewis Simplified Licensing and Server Versions by Kevin Remde I Think, Therefore IPAM! by Kevin Remde Windows Server 2012 and the RSATs by Kevin Remde Top 3 New Tricks in the Active Directory Admin Center by Keith Mayer Dynamic Access Control by Brian Lewis Get the Gremlin out of Your Active Directory Virtualized Infrastructure by Matt Hester Scoping out the New DHCP Failover by Keith Mayer Gone in 8 Seconds – The New CHKDSK by Matt Hester New Remote Desktop Services (RDS) by Brian Lewis No Better Time Than Now to Choose Hyper-V by Matt Hester What’s Next? Keep Learning! Want to learn more about Windows Server 2012 and Hyper-V Server 2012?  Want to prepare for certification on Windows Server 2012? Do It: Join our Windows Server 2012 “Early Experts” Challenge online peer study group for FREE at http://earlyexperts.net. You’ll get FREE access to video-based lectures, structured study materials and hands-on lab activities to help you study and prepare!  Along the way, you’ll be part of an IT Pro community of over 1,000+ IT Pros that are all helping each other learn Windows Server 2012! What are Your Favorite Features? Do you have a Favorite Feature in Windows Server 2012 that we missed in our list above?  Feel free to share your favorites in the comments below! Keith Build Your Lab! Download Windows Server 2012 Don’t Have a Lab? Build Your Lab in the Cloud with Windows Azure Virtual Machines Want to Get Certified? Join our Windows Server 2012 "Early Experts" Study Group

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  • SQL SERVER – Difference Between DATETIME and DATETIME2

    - by pinaldave
    Yesterday I have written a very quick blog post on SQL SERVER – Difference Between GETDATE and SYSDATETIME and I got tremendous response for the same. I suggest you read that blog post before continuing this blog post today. I had asked people to honestly take part and share their view about above two system function. There are few emails as well few comments on the blog post asking question how did I come to know the difference between the same. The answer is real world issues. I was called in for performance tuning consultancy where I was asked very strange question by one developer. Here is the situation he was facing. System had a single table with two different column of datetime. One column was datelastmodified and second column was datefirstmodified. One of the column was DATETIME and another was DATETIME2. Developer was populating them with SYSDATETIME respectively. He was always thinking that the value inserted in the table will be the same. This table was only accessed by INSERT statement and there was no updates done over it in application.One fine day he ran distinct on both of this column and was in for surprise. He always thought that both of the table will have same data, but in fact they had very different data. He presented this scenario to me. I said this can not be possible but when looked at the resultset, I had to agree with him. Here is the simple script generated to demonstrate the problem he was facing. This is just a sample of original table. DECLARE @Intveral INT SET @Intveral = 10000 CREATE TABLE #TimeTable (FirstDate DATETIME, LastDate DATETIME2) WHILE (@Intveral > 0) BEGIN INSERT #TimeTable (FirstDate, LastDate) VALUES (SYSDATETIME(), SYSDATETIME()) SET @Intveral = @Intveral - 1 END GO SELECT COUNT(DISTINCT FirstDate) D_GETDATE, COUNT(DISTINCT LastDate) D_SYSGETDATE FROM #TimeTable GO SELECT DISTINCT a.FirstDate, b.LastDate FROM #TimeTable a INNER JOIN #TimeTable b ON a.FirstDate = b.LastDate GO SELECT * FROM #TimeTable GO DROP TABLE #TimeTable GO Let us see the resultset. You can clearly see from result that SYSDATETIME() does not populate the same value in the both of the field. In fact the value is either rounded down or rounded up in the field which is DATETIME. Event though we are populating the same value, the values are totally different in both the column resulting the SELF JOIN fail and display different DISTINCT values. The best policy is if you are using DATETIME use GETDATE() and if you are suing DATETIME2 use SYSDATETIME() to populate them with current date and time to accurately address the precision. As DATETIME2 is introduced in SQL Server 2008, above script will only work with SQL SErver 2008 and later versions. I hope I have answered few questions asked yesterday. Reference: Pinal Dave (http://www.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL DateTime, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Oracle Data Mining a Star Schema: Telco Churn Case Study

    - by charlie.berger
    There is a complete and detailed Telco Churn case study "How to" Blog Series just posted by Ari Mozes, ODM Dev. Manager.  In it, Ari provides detailed guidance in how to leverage various strengths of Oracle Data Mining including the ability to: mine Star Schemas and join tables and views together to obtain a complete 360 degree view of a customer combine transactional data e.g. call record detail (CDR) data, etc. define complex data transformation, model build and model deploy analytical methodologies inside the Database  His blog is posted in a multi-part series.  Below are some opening excerpts for the first 3 blog entries.  This is an excellent resource for any novice to skilled data miner who wants to gain competitive advantage by mining their data inside the Oracle Database.  Many thanks Ari! Mining a Star Schema: Telco Churn Case Study (1 of 3) One of the strengths of Oracle Data Mining is the ability to mine star schemas with minimal effort.  Star schemas are commonly used in relational databases, and they often contain rich data with interesting patterns.  While dimension tables may contain interesting demographics, fact tables will often contain user behavior, such as phone usage or purchase patterns.  Both of these aspects - demographics and usage patterns - can provide insight into behavior.Churn is a critical problem in the telecommunications industry, and companies go to great lengths to reduce the churn of their customer base.  One case study1 describes a telecommunications scenario involving understanding, and identification of, churn, where the underlying data is present in a star schema.  That case study is a good example for demonstrating just how natural it is for Oracle Data Mining to analyze a star schema, so it will be used as the basis for this series of posts...... Mining a Star Schema: Telco Churn Case Study (2 of 3) This post will follow the transformation steps as described in the case study, but will use Oracle SQL as the means for preparing data.  Please see the previous post for background material, including links to the case study and to scripts that can be used to replicate the stages in these posts.1) Handling missing values for call data recordsThe CDR_T table records the number of phone minutes used by a customer per month and per call type (tariff).  For example, the table may contain one record corresponding to the number of peak (call type) minutes in January for a specific customer, and another record associated with international calls in March for the same customer.  This table is likely to be fairly dense (most type-month combinations for a given customer will be present) due to the coarse level of aggregation, but there may be some missing values.  Missing entries may occur for a number of reasons: the customer made no calls of a particular type in a particular month, the customer switched providers during the timeframe, or perhaps there is a data entry problem.  In the first situation, the correct interpretation of a missing entry would be to assume that the number of minutes for the type-month combination is zero.  In the other situations, it is not appropriate to assume zero, but rather derive some representative value to replace the missing entries.  The referenced case study takes the latter approach.  The data is segmented by customer and call type, and within a given customer-call type combination, an average number of minutes is computed and used as a replacement value.In SQL, we need to generate additional rows for the missing entries and populate those rows with appropriate values.  To generate the missing rows, Oracle's partition outer join feature is a perfect fit.  select cust_id, cdre.tariff, cdre.month, minsfrom cdr_t cdr partition by (cust_id) right outer join     (select distinct tariff, month from cdr_t) cdre     on (cdr.month = cdre.month and cdr.tariff = cdre.tariff);   ....... Mining a Star Schema: Telco Churn Case Study (3 of 3) Now that the "difficult" work is complete - preparing the data - we can move to building a predictive model to help identify and understand churn.The case study suggests that separate models be built for different customer segments (high, medium, low, and very low value customer groups).  To reduce the data to a single segment, a filter can be applied: create or replace view churn_data_high asselect * from churn_prep where value_band = 'HIGH'; It is simple to take a quick look at the predictive aspects of the data on a univariate basis.  While this does not capture the more complex multi-variate effects as would occur with the full-blown data mining algorithms, it can give a quick feel as to the predictive aspects of the data as well as validate the data preparation steps.  Oracle Data Mining includes a predictive analytics package which enables quick analysis. begin  dbms_predictive_analytics.explain(   'churn_data_high','churn_m6','expl_churn_tab'); end; /select * from expl_churn_tab where rank <= 5 order by rank; ATTRIBUTE_NAME       ATTRIBUTE_SUBNAME EXPLANATORY_VALUE RANK-------------------- ----------------- ----------------- ----------LOS_BAND                                      .069167052          1MINS_PER_TARIFF_MON  PEAK-5                   .034881648          2REV_PER_MON          REV-5                    .034527798          3DROPPED_CALLS                                 .028110322          4MINS_PER_TARIFF_MON  PEAK-4                   .024698149          5From the above results, it is clear that some predictors do contain information to help identify churn (explanatory value > 0).  The strongest uni-variate predictor of churn appears to be the customer's (binned) length of service.  The second strongest churn indicator appears to be the number of peak minutes used in the most recent month.  The subname column contains the interior piece of the DM_NESTED_NUMERICALS column described in the previous post.  By using the object relational approach, many related predictors are included within a single top-level column. .....   NOTE:  These are just EXCERPTS.  Click here to start reading the Oracle Data Mining a Star Schema: Telco Churn Case Study from the beginning.    

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  • Introducing SQL Server 2008 and 2008 R2 Integration Services

    The latest release of SSIS strengthens its position as one of the primary foundations of Business Intelligence, delivering a powerful framework for solutions that combine data from disparate sources, facilitating its analysis and reporting. Join Marcin Policht as he reviews its general characteristics.

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  • Mark Hurd and Balaji Yelamanchili present Oracle’s Business Analytics Strategy

    - by swalker
    Join Mark Hurd and Balaji Yelamanchili as they unveil the latest advances in Oracle’s strategy for placing analytics into the hands of every decision-makers—so that they can see more, think smarter, and act faster. Wednesday, April 4, 2012 at 1.0 pm UK BST / 2.0 pm CET Register HERE today for this online event Agenda Keynote: Oracle’s Business Analytics StrategyMark Hurd, President, Oracle, and Balaji Yelamanchili, Senior Vice President, Analytics and Performance Management, Oracle Plus Breakout Sessions: Achieving Predictable Performance with Oracle Hyperion Enterprise Performance Managemen Explore All Relevant Data—Introducing Oracle Endeca Information Discovery Run Your Business Faster and Smarter with Oracle Business Intelligence Applications on Oracle Exalytics In-Memory Machine Analyzing and Deciding with Big Data

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