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  • Linq Query with aggregate function

    - by Billy Logan
    Hello everyone, I am trying to figure out how to go about writing a linq query to perform an aggregate like the sql query below: select d.ID, d.FIRST_NAME, d.LAST_NAME, count(s.id) as design_count from tbldesigner d inner join TBLDESIGN s on d.ID = s.DESIGNER_ID where s.COMPLETED = 1 and d.ACTIVE = 1 group by d.ID, d.FIRST_NAME, d.LAST_NAME Having COUNT(s.id) > 0 If this is even possible with a linq query could somebody please provide me with an example. Thanks in Advance, Billy

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  • Why use multiple OpenGL context

    - by Luca
    For rendering I have a current GL context, associated to a window. In the case the application render multiple scenes (for example using accumulation or different viewports) I think it is ok to reuse the same context. My question, indeed, is: why should I use multiple GL context? I red on ARB_framebuffer_object extension spec that MakeCurrent call could be expansive, and in the case the ARB_framebuffer_object extension is present I can render on a generic buffer without using MakeCurrent. Apparently the only reason to use multiple GL context is to avoid to setup context state (pixel store, transfer, point size, polygon stipple...) or to have avaialable multiple render buffers configuration (one context with accumulation, another without). How to determine when is better an alternative context instead of setting context state? Thankyou all!

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  • Can't select data from MySQL database: java.lang.NullPointerException

    - by Devel
    Hi, I'm trying to select data from database using this code: //DATABASE ResultSet rs; String polecenie; Statement st; String[] subj; public void polacz() { try { Class.forName("com.mysql.jdbc.Driver"); Connection pol=DriverManager.getConnection("jdbc:mysql://localhost:3306/testgenerator", "root", "pospaz"); st = pol.createStatement(); lblPolaczonoZBaza.setText("Polaczono z baza danych testgenerator"); } catch (Exception ek) { statusMessageLabel.setText("Can't connect to d: "+ek); } polecenie = "select * from subjects"; try { rs = st.executeQuery(polecenie); int i=0; while (rs.next()){ subj[i] = rs.getString("name"); i++; } st.close(); } catch (Exception ek) { statusMessageLabel.setText("Can't select data: "+ek); } } The second catch shows exception: java.lang.NullPointerException I looked everywhere and I can't find the solution. I'd be grateful for any help.

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  • C# and SQL - sub select from a table parameter

    - by Dr.HappyPants
    Below is a code snippet for passing a table as a parameter to a query that can be used in Sql Server 2008. I'm confused though about the "SELECT id.custid FROM @custids id". Why does it use id.custid and @custids id...? private static void datatable_example() { string [] custids = {"ALFKI", "BONAP", "CACTU", "FRANK"}; DataTable custid_list = new DataTable(); custid_list.Columns.Add("custid", typeof(String)); foreach (string custid in custids) { DataRow dr = custid_list.NewRow(); dr["custid"] = custid; custid_list.Rows.Add(dr); } using(SqlConnection cn = setup_connection()) { using(SqlCommand cmd = cn.CreateCommand()) { cmd.CommandText = @"SELECT C.CustomerID, C.CompanyName FROM Northwind.dbo.Customers C WHERE C.CustomerID IN (SELECT id.custid FROM @custids id)"; cmd.CommandType = CommandType.Text; cmd.Parameters.Add("@custids", SqlDbType.Structured); cmd.Parameters["@custids"].Direction = ParameterDirection.Input; cmd.Parameters["@custids"].TypeName = "custid_list_tbltype"; cmd.Parameters["@custids"].Value = custid_list; using (SqlDataAdapter da = new SqlDataAdapter(cmd)) using (DataSet ds = new DataSet()) { da.Fill(ds); PrintDataSet(ds); } } }

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  • Access: Data Type Mismatch using boolean function in query criteria

    - by BenV
    I have a VBA function IsValidEmail() that returns a boolean. I have a query that calls this function: Expr1: IsValidEmail([E-Mail]). When I run the query, it shows -1 for True and 0 for False. So far so good. Now I want to filter the query to only show invalid emails. I'm using the Query Designer, so I just add a value of 0 to the Criteria field. This gives me a "Data Type Mismatch" error. So does "0" (with quotes) and False. How am I supposed to specify criteria for a boolean function?

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  • LINQ Query please help C#.Net.

    - by Paul Matthews
    I'm very new to LINQ and struggling to find the answers. I have a simple SQL query. Select ID, COUNT(ID) as Selections, OptionName, SUM(Units) as Units FROM tbl_Results GROUP BY ID, OptionName. The results I got were: '1' '4' 'Approved' '40' '2' '1' 'Rejected' '19' '3' '2' 'Not Decided' '12' Due to having to encrypt all my data in the database I'm unable to do sums. Therefore I have now brought back the data and decrypt it in the application layer. Results would be: '1' 'Approved' '10' '3' 'Not Deceided' '6' '2' 'Rejected' '19' '1' 'Approved' '15' '1' 'Approved' '5' '3' 'Not Deceided' '6' '1' 'Approved' '10' using a simple class I have called back the above results, and put them in a list class. public class results { public int ID {get;set;} public string OptionName {get;set;} public int Unit {get;set;} } I almost have the LINQ query to bring back the results like the SQL query at the top var q = from r in Results group p.Unit by p.ID int g select new {ID = g.Key, Selections = g.Count(), Units = g.Sum()}; How do I ensure my LINQ query also give me the Option Name? Also if I created a class called Statistics to hold my results how would I modify the LINQ query to give me list result set? public class results { public int ID {get;set;} public int NumberOfSelections { get; set; } public string OptionName {get;set;} public int UnitTotal {get;set;} }

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  • Why does a conditional not affect query speed?

    - by Telos
    I have a stored procedure that was taking a "long" period of time to execute. The query only needs to return data in one case, so I figured I could check for that case and just return before hitting the actual query. The only problem is that it still takes the same amount of time to execute with an if statement. I have verified that the code inside the if is not executing, and that if I replace the complex query with a simple select the speed is fine... so now I'm confused. Why is the query being slowed down by code that doesn't get executed when the conditional is false? Here's the query itself: ALTER PROCEDURE [dbo].[pr_cbc_GetCokeInfo] @pa_record int, @pb_record int AS BEGIN SET NOCOUNT ON; declare @ticketRec int SELECT @ticketRec = TicketRecord FROM eservice_live..v_sdticket where TicketRecord=@pa_record AND serviceCompanyID = 1139 AND @pb_record IS NULL if @ticketRec IS NULL return select record = null, doc_ref = @pa_record, memo_type = 'I', memo = 'Bottler: ' + isnull(Bottler, '') + ' ' + 'Sales Loc: ' + isnull(SalesLocation, '') + ' ' + 'Outlet Desc: ' + isnull(OutletDesc, '') + ' ' + 'City: ' + isnull(OutletCity, '') + ' ' + 'EquipNo: ' + isnull(EquipNo, '') + ' ' + 'SerialNo: ' + isnull(SerialNo, '') + ' ' + 'PhaseNo: ' + isnull(cast(PhaseNo as varchar(255)), '') + ' ' + 'StaticIP: ' + isnull(StaticIP, '') + ' ' + 'Air Card: ' + isnull(AirCard, '') FROM eservice_live..v_SDExtendedInfoField ef JOIN eservice_live..CokeSNList csl ON ef.valueText=csl.SerialNo where ef.docType='CLH' AND ef.docref = @ticketRec AND ef.ExtendedDocNumber=5 SET NOCOUNT OFF; END

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  • MySQL - Calculating a value from two columns in each row, using the result in a WHERE or HAVING clause

    - by taber
    I have a MySQL db schema like so: id flags views done ------------------------------- 1 2 20 0 2 66 100 0 3 25 40 0 4 30 60 0 ... thousands of rows ... I want to update all of the rows whose flags / views are = 0.2. First as a test I want to try to SELECT to see how many rows would actually get updated. I tried: SELECT flags/views AS poncho FROM mytable HAVING poncho 0.2 But this only returns like 2 rows and I know there should be a lot more than that. It seems like it's calculating the poncho value on all rows or something odd. What am I doing wrong? Thanks!

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  • Multiple row Tabs using CSS

    - by Jack
    Hello, i can't find a way to do multiple row tabs with ASP.net ajax tab control. I also can't find a tutorial or example on using CSS to make multiple row of tabs. In case you don't understand what i'm looking for here is a image of what i'm looking for http://bp1.blogger.com/_WCGCQYWEaxs/Rq1c2bLNMDI/AAAAAAAAABU/0sKw_CrKLL4/s1600-h/dsd.jpg Can someone give me a link on how to achieve multiple row of tabs?

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  • SharePoint 2010 Search Query

    - by Faiz
    Hi, I had written a custom search query for MOSS 2007 to get data where contenttype is post. However the same query is not returning any results in SharePoint 2010. Any inputs will be appreciated. Please note that SharePoint search box is returning (parameter k in query string and also contenttype:post) appropriate results. Thanks

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  • Another IKImageView Question: copying a region

    - by Brian Postow
    I'm trying to use the select and copy feature of the IKImageView. If all you want to do is have an app with an image, select a portion and copy it to the clipboard, it's easy. You set the copy menu pick to the first responder's copy:(id) method and magically everything works. However, if you want something more complicated, like you want to copy as part of some other operation, I can't seem to find the method to do this. IKImageView doesn't seem to have a copy method, it doesn't seem to have a method that will even tell you the selected rectangle! I have gone through Hillegass' book, so I understand how the clipboard works, just not how to get the portion of the image out of the view... Now, I'm starting to think that I made a mistake in basing my project on IKImageView, but it's what Preview is built on (or so I've read), so I figured it had to be stable... and anyway, now it's too late, I'm too deep in this to start over... So, other than not using IKImageView, any suggestions on how to copy the select region to the clipboard manually? EDIT actually, I have found the copy(id) method, but when I call it, I get <Error>: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 16 bits/pixel; 1-component color space; kCGImageAlphaPremultipliedLast; 2624 bytes/row. Which obviously doesn't happen when I do a normal copy through the first-responder... I understand the error message, but I'm not sure where it's getting those parameters from... Is there any way to trace through this and see how this is happening? A debugger won't help for obvious reasons, as well as the fact that I'm doing this in Mozilla, so a debugger isn't an option anyway... EDIT 2 It occurs to me that the copy:(id) method I found may be copying the VIEW rather than copying a chunk of the image to the clipboard, which is what I need. The reason I thought it was the clipboard copy is that in another project, where I'm copying from an IKImageView to the clipboard straight from the edit menu, it just sends a copy:(id) to the firstResponder, but I'm not actually sure what the firstresponder does with it...

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  • Query notation for the sitecore 'source' field in template builder

    - by M.R.
    I am trying to set the the source field of a template using the query notation (or xpath - whichever works), but none of them seems to be working. My content tree is a multisite content tree: France --Page 1 ----Page1A -------Page1AA --Page 2 --Page 3 --METADATA ----Regions US --Page 1 ----Page1A -------Page1AA --Page 2 --Page 3 --METADATA ----Regions Each site has its own METADATA folder, and I want it so that when adding a page inside each of the main country nodes, I want the values to reflect whatever is in the METADATA of that site. I have two different fields for now - a droplink and a treelistex field. So I thought I can just get the parent item that is a country site, and get the metadata folder for that. When I put the following query in both the fields, I get different results: query:./ancestor::*[@@templatename='CountryHome']/METADATA/Regions/* For the droplink field, I get only the first Region (one item) For the treelistex field, I get the entire content tree I then tried to modify the query a little bit and took the 'query' notation out ./ancestor::*[@@templatename='CountryHome']/METADATA/Regions/* If I go to the developer center/xpath builder, and set the context node to any item underneath the main country site, it returns me exactly what I need, but when I put this in the source, I get the entire content tree in both the cases. Help!

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  • Rails 3 equivalent of complex SQL query

    - by Bryan
    Given the following models: class Recipe < ActiveRecord::Base has_many :recipe_ingredients has_many :ingredients, :through => :recipe_ingredients end class RecipeIngredient < ActiveRecord::Base belongs_to :recipe belongs_to :ingredient end class Ingredient < ActiveRecord::Base end How can I perform the following SQL query using Arel in Rails 3? SELECT * FROM recipes WHERE NOT EXISTS ( SELECT * FROM ingredients WHERE name IN ('chocolate', 'cream') AND NOT EXISTS ( SELECT * FROM recipe_ingredients WHERE recipe_ingredients.recipe_id = recipes.id AND recipe_ingredients.ingredient_id = ingredients.id))

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  • MySql Query lag time / deadlock?

    - by Click Upvote
    When there are multiple PHP scripts running in parallel, each making an UPDATE query to the same record in the same table repeatedly, is it possible for there to be a 'lag time' before the table is updated with each query? I have basically 5-6 instances of a PHP script running in parallel, having been launched via cron. Each script gets all the records in the items table, and then loops through them and processes them. However, to avoid processing the same item more than once, I store the id of the last item being processed in a seperate table. So this is how my code works: function getCurrentItem() { $sql = "SELECT currentItemId from settings"; $result = $this->db->query($sql); return $result->get('currentItemId'); } function setCurrentItem($id) { $sql = "UPDATE settings SET currentItemId='$id'"; $this->db->query($sql); } $currentItem = $this->getCurrentItem(); $sql = "SELECT * FROM items WHERE status='pending' AND id > $currentItem'"; $result = $this->db->query($sql); $items = $result->getAll(); foreach ($items as $i) { //Check if $i has been processed by a different instance of the script, and if so, //leave it untouched. if ($this->getCurrentItem() > $i->id) continue; $this->setCurrentItem($i->id); // Process the item here } But despite of all the precautions, most items are being processed more than once. Which makes me think that there is some lag time between the update queries being run by the PHP script, and when the database actually updates the record. Is it true? And if so, what other mechanism should I use to ensure that the PHP scripts always get only the latest currentItemId even when there are multiple scripts running in parrallel? Would using a text file instead of the db help?

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  • Poor execution plans when using a filter and CONTAINSTABLE in a query

    - by Paul McLoughlin
    We have an interesting problem that I was hoping someone could help to shed some light on. At a high level the problem is as below: The following query executes quickly (1 second): SELECT SA.* FROM cg.SEARCHSERVER_ACTYS AS SA JOIN CONTAINSTABLE(CG.SEARCHSERVER_ACTYS, NOTE, 'reports') AS T1 ON T1.[Key]=SA.UNIQUE_ID but if we add a filter to the query, then it takes approximately 2 minutes to return: SELECT SA.* FROM cg.SEARCHSERVER_ACTYS AS SA JOIN CONTAINSTABLE(CG.SEARCHSERVER_ACTYS, NOTE, 'reports') AS T1 ON T1.[Key]=SA.UNIQUE_ID WHERE SA.CHG_DATE'19 Feb 2010' Looking at the execution plan for the two queries, I can see that in the second case there are two places where there are huge differences between the actual and estimated number of rows, these being: 1) For the FulltextMatch table valued function where the estimate is approx 22,000 rows and the actual is 29 million rows (which are then filtered down to 1670 rows before the join) and 2) For the index seek on the full text index, where the estimate is 1 row and the actual is 13,000 rows As a result of the estimates, the optimiser is choosing to use a nested loops join (since it assumes a small number of rows) hence the plan is inefficient. We can work around the problem by either (a) parameterising the query and adding an OPTION (OPTIMIZE FOR UNKNOWN) to the query or (b) by forcing a HASH JOIN to be used. In both of these cases the query returns in sub 1 second and the estimates appear reasonable. My question really is 'why are the estimates being used in the poorly performing case so wildly inaccurate and what can be done to improve them'? Statistics are up to date on the indexes on the indexed view being used here. Any help greatly appreciated.

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  • Django aggregate query generating SQL error

    - by meepmeep
    I'm using Django 1.1.1 on a SQL Server 2005 db using the latest sqlserver_ado library. models.py includes: class Project(models.Model): name = models.CharField(max_length=50) class Thing(models.Model): project = models.ForeignKey(Project) reference = models.CharField(max_length=50) class ThingMonth(models.Model): thing = models.ForeignKey(Thing) timestamp = models.DateTimeField() ThingMonthValue = models.FloatField() class Meta: db_table = u'ThingMonthSummary' In a view, I have retrieved a queryset called 'things' which contains 25 Things: things = Thing.objects.select_related().filter(project=1).order_by('reference') I then want to do an aggregate query to get the average ThingMonthValue for the first 20 of those Things for a certain period, and the same value for the last 5. For the first 20 I do: averageThingMonthValue = ThingMonth.objects.filter(turbine__in=things[:20],timestamp__range="2009-01-01 00:00","2010-03-00:00")).aggregate(Avg('ThingMonthValue'))['ThingMonthValue__avg'] This works fine, and returns the desired value. For the last 5 I do: averageThingMonthValue = ThingMonth.objects.filter(turbine__in=things[20:],timestamp__range="2009-01-01 00:00","2010-03-00:00")).aggregate(Avg('ThingMonthValue'))['ThingMonthValue__avg'] But for this I get an SQL error: 'Only one expression can be specified in the select list when the subquery is not introduced with EXISTS.' The SQL query being used by django reads: SELECT AVG([ThingMonthSummary].[ThingMonthValue]) AS [ThingMonthValue__avg] FROM [ThingMonthSummary] WHERE ([ThingMonthSummary].[thing_id] IN (SELECT _row_num, [id] FROM ( SELECT ROW_NUMBER() OVER ( ORDER BY [AAAA].[id] ASC) as _row_num, [AAAA].[id] FROM ( SELECT U0.[id] FROM [Thing] U0 WHERE U0.[project_id] = 1 ) AS [AAAA]) as QQQ where 20 < _row_num) AND [ThingMonthSummary].[timestamp] BETWEEN '01/01/09 00:00:00' and '03/01/10 00:00:00') Any idea why it works for one slice of the Things and not the second? I've checked and the two slices do contain the desired Things correctly.

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  • PHP: using REGEX to get the tablename from a mysql query

    - by Matt
    Hi Guys, Consider these three mysql statements: select * from Users; select id, title, value from Blogs; select id, feelURL, feelTitle from Feeds where id = 1; Now im not very good at REGEX, but i want to get the table name from the mysql query. Could someone possibly create one for me with a little explanation. Thanks,

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  • How to set drop down list option up to specific value

    - by bugbug
    If I have valvo that obtain from database, How can I set volvo option status into active(checked) by using JQuery? <select name="car"> <option value="volvo">Volvo</option> <option value="saab">Saab</option> <option value="mercedes">Mercedes</option> <option value="audi">Audi</option> </select> I don't know how to manager control that have same identity. ??? $('input[name="car"]').attr('checked', true);

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  • return sql query in xml format in python

    - by Ramy
    When I first started working at the company that i work at now, I created a java application that would run batches of jasper-reports. In order to determine which parameters to use for each report in the set of reports, I run a sql query (on sqlserver). I wrote the application to take an xml file with a set of parameters for each report to be generated in the set. so, my process has become, effectively, three steps: run the sql query and return the results in XML format (using 'for XML auto') run the results of the sql query through an XSLT transformation so the xml is formatted in such a way that is friendly with the java application i wrote. run the java application with that final xml file As you can imagine, what I'd like to do is accomplish these steps in python, but i'm not quite sure how to get started. I know how to run an SQL query in Python. I see plenty of documentation about how to write your own xml document with Python. I even see documentation for xsl transformations in python. the big question is how to get the results of the sql query in XML through python. Any and all pointers would be very valuable. Thanks, _Ramy

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  • vb.net date format from textbox > MS SQL query

    - by Jonesy
    Hi folks, I have a date column in a DB tabel that I want to query using a date taken from textbox.text. the user selects a date from the calendar in the format dd/MM/yyyy. I want to use that date to put into a query. How do i format the date to be able to query the database? Dim datefrom As String =txtDateFrom.Text Dim dateto As String =txtDateTo.Text The query will look like this: WHERE (tblClient.ClientID = " & ClientID & ") AND (tblBackupArchive.BackupDate BETWEEN '" + datefrom + "' AND '" + dateto + "')" I'm using MS SQL Server btw. Any help most appreciated. Jonesy

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  • Windows 7 - Disable <ctrl + monitor#> screen switching functionality

    - by jdavis
    In windows 7, when I have multiple monitors extending my desktop, there is functionality to activate a certain monitor by pressing 'ctrl' + . So if I press 'ctrl' + 2, then the current program jumps over to the monitor identified as monitor 2. I'm sure this functionality serves a good purpose, but it can be rather anoying in programs that rely on 'ctrl' + # for other functionality. Is there a way to disable this feature in windows?

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  • Strange: Planner takes decision with lower cost, but (very) query long runtime

    - by S38
    Facts: PGSQL 8.4.2, Linux I make use of table inheritance Each Table contains 3 million rows Indexes on joining columns are set Table statistics (analyze, vacuum analyze) are up-to-date Only used table is "node" with varios partitioned sub-tables Recursive query (pg = 8.4) Now here is the explained query: WITH RECURSIVE rows AS ( SELECT * FROM ( SELECT r.id, r.set, r.parent, r.masterid FROM d_storage.node_dataset r WHERE masterid = 3533933 ) q UNION ALL SELECT * FROM ( SELECT c.id, c.set, c.parent, r.masterid FROM rows r JOIN a_storage.node c ON c.parent = r.id ) q ) SELECT r.masterid, r.id AS nodeid FROM rows r QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------------------------------------- CTE Scan on rows r (cost=2742105.92..2862119.94 rows=6000701 width=16) (actual time=0.033..172111.204 rows=4 loops=1) CTE rows -> Recursive Union (cost=0.00..2742105.92 rows=6000701 width=28) (actual time=0.029..172111.183 rows=4 loops=1) -> Index Scan using node_dataset_masterid on node_dataset r (cost=0.00..8.60 rows=1 width=28) (actual time=0.025..0.027 rows=1 loops=1) Index Cond: (masterid = 3533933) -> Hash Join (cost=0.33..262208.33 rows=600070 width=28) (actual time=40628.371..57370.361 rows=1 loops=3) Hash Cond: (c.parent = r.id) -> Append (cost=0.00..211202.04 rows=12001404 width=20) (actual time=0.011..46365.669 rows=12000004 loops=3) -> Seq Scan on node c (cost=0.00..24.00 rows=1400 width=20) (actual time=0.002..0.002 rows=0 loops=3) -> Seq Scan on node_dataset c (cost=0.00..55001.01 rows=3000001 width=20) (actual time=0.007..3426.593 rows=3000001 loops=3) -> Seq Scan on node_stammdaten c (cost=0.00..52059.01 rows=3000001 width=20) (actual time=0.008..9049.189 rows=3000001 loops=3) -> Seq Scan on node_stammdaten_adresse c (cost=0.00..52059.01 rows=3000001 width=20) (actual time=3.455..8381.725 rows=3000001 loops=3) -> Seq Scan on node_testdaten c (cost=0.00..52059.01 rows=3000001 width=20) (actual time=1.810..5259.178 rows=3000001 loops=3) -> Hash (cost=0.20..0.20 rows=10 width=16) (actual time=0.010..0.010 rows=1 loops=3) -> WorkTable Scan on rows r (cost=0.00..0.20 rows=10 width=16) (actual time=0.002..0.004 rows=1 loops=3) Total runtime: 172111.371 ms (16 rows) (END) So far so bad, the planner decides to choose hash joins (good) but no indexes (bad). Now after doing the following: SET enable_hashjoins TO false; The explained query looks like that: QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- CTE Scan on rows r (cost=15198247.00..15318261.02 rows=6000701 width=16) (actual time=0.038..49.221 rows=4 loops=1) CTE rows -> Recursive Union (cost=0.00..15198247.00 rows=6000701 width=28) (actual time=0.032..49.201 rows=4 loops=1) -> Index Scan using node_dataset_masterid on node_dataset r (cost=0.00..8.60 rows=1 width=28) (actual time=0.028..0.031 rows=1 loops=1) Index Cond: (masterid = 3533933) -> Nested Loop (cost=0.00..1507822.44 rows=600070 width=28) (actual time=10.384..16.382 rows=1 loops=3) Join Filter: (r.id = c.parent) -> WorkTable Scan on rows r (cost=0.00..0.20 rows=10 width=16) (actual time=0.001..0.003 rows=1 loops=3) -> Append (cost=0.00..113264.67 rows=3001404 width=20) (actual time=8.546..12.268 rows=1 loops=4) -> Seq Scan on node c (cost=0.00..24.00 rows=1400 width=20) (actual time=0.001..0.001 rows=0 loops=4) -> Bitmap Heap Scan on node_dataset c (cost=58213.87..113214.88 rows=3000001 width=20) (actual time=1.906..1.906 rows=0 loops=4) Recheck Cond: (c.parent = r.id) -> Bitmap Index Scan on node_dataset_parent (cost=0.00..57463.87 rows=3000001 width=0) (actual time=1.903..1.903 rows=0 loops=4) Index Cond: (c.parent = r.id) -> Index Scan using node_stammdaten_parent on node_stammdaten c (cost=0.00..8.60 rows=1 width=20) (actual time=3.272..3.273 rows=0 loops=4) Index Cond: (c.parent = r.id) -> Index Scan using node_stammdaten_adresse_parent on node_stammdaten_adresse c (cost=0.00..8.60 rows=1 width=20) (actual time=4.333..4.333 rows=0 loops=4) Index Cond: (c.parent = r.id) -> Index Scan using node_testdaten_parent on node_testdaten c (cost=0.00..8.60 rows=1 width=20) (actual time=2.745..2.746 rows=0 loops=4) Index Cond: (c.parent = r.id) Total runtime: 49.349 ms (21 rows) (END) - incredibly faster, because indexes were used. Notice: Cost of the second query ist somewhat higher than for the first query. So the main question is: Why does the planner make the first decision, instead of the second? Also interesing: Via SET enable_seqscan TO false; i temp. disabled seq scans. Than the planner used indexes and hash joins, and the query still was slow. So the problem seems to be the hash join. Maybe someone can help in this confusing situation? thx, R.

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  • How to perform Linq select new with datetime in SQL 2008

    - by kd7iwp
    In our C# code I recently changed a line from inside a linq-to-sql select new query as follows: OrderDate = (p.OrderDate.HasValue ? p.OrderDate.Value.Year.ToString() + "-" + p.OrderDate.Value.Month.ToString() + "-" + p.OrderDate.Value.Day.ToString() : "") To: OrderDate = (p.OrderDate.HasValue ? p.OrderDate.Value.ToString("yyyy-mm-dd") : "") The change makes the line smaller and cleaner. It also works fine with our SQL 2008 database in our development environment. However, when the code deployed to our production environment which uses SQL 2005 I received an exception stating: Nullable Type must have a value. For further analysis I copied (p.OrderDate.HasValue ? p.OrderDate.Value.ToString("yyyy-mm-dd") : "") into a string (outside of a Linq statement) and had no problems at all, so it only causes an in issue inside my Linq. Is this problem just something to do with SQL 2005 using different date formats than from SQL 2008? Here's more of the Linq: dt = FilteredOrders.Where(x => x != null).Select(p => new { Order = p.OrderId, link = "/order/" + p.OrderId.ToString(), StudentId = (p.PersonId.HasValue ? p.PersonId.Value : 0), FirstName = p.IdentifierAccount.Person.FirstName, LastName = p.IdentifierAccount.Person.LastName, DeliverBy = p.DeliverBy, OrderDate = p.OrderDate.HasValue ? p.OrderDate.Value.Date.ToString("yyyy-mm-dd") : ""}).ToDataTable(); This is selecting from a List of Order objects. The FilteredOrders list is from another linq-to-sql query and I call .AsEnumerable on it before giving it to this particular select new query. Doing this in regular code works fine: if (o.OrderDate.HasValue) tempString += " " + o.OrderDate.Value.Date.ToString("yyyy-mm-dd");

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