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  • SQL SERVER – Merge Two Columns into a Single Column

    - by Pinal Dave
    Here is a question which I have received from user yesterday. Hi Pinal, I want to build queries in SQL server that merge two columns of the table If I have two columns like, Column1 | Column2 1                5 2                6 3                7 4                8 I want to output like, Column1 1 2 3 4 5 6 7 8 It is a good question. Here is how we can do achieve the task. I am making the assumption that both the columns have different data and there is no duplicate. USE TempDB GO CREATE TABLE TestTable (Col1 INT, Col2 INT) GO INSERT INTO TestTable (Col1, Col2) SELECT 1, 5 UNION ALL SELECT 2, 6 UNION ALL SELECT 3, 7 UNION ALL SELECT 4, 8 GO SELECT Col1 FROM TestTable UNION SELECT Col2 FROM TestTable GO DROP TABLE TestTable GO Here is the original table. Here is the result table. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • T-SQL Tuesday: What kind of Bookmark are you using?

    - by Kalen Delaney
    I’m glad there is no minimum length requirement for T-SQL Tuesday blog posts , because this one will be short. I was in the classroom for almost 11 hours today, and I need to be back tomorrow morning at 7:30. Way long ago, back in SQL 2000 (or was it earlier?) when a query indicated that SQL Server was going to use a nonclustered index to get row pointers, and then look up those rows in the underlying table, the plan just had a very linear look to it. The operator that indicated going from the nonclustered...(read more)

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  • SQL query duplicating results [on hold]

    - by Ben
    I have written a query that results in data being retrieved for the top 5 customers in my table per account manager. Here is the query: SELECT account_manager_id, mgap_ska_id, total FROM (SELECT account_manager_id, mgap_ska_id, mgap_growth + mgap_recovery AS total, @grp_rank := IF(@current_accmanid = account_manager_id, @grp_rank + 1, 1) AS grp_rank, @current_accmanid := account_manager_id FROM mgap_orders ORDER BY total DESC ) ranked WHERE grp_rank <= 5 and here is the result of the query: account_manager_id mgap_ska_id total 159840 5062352 61569.21 159840 5062352 61569.21 159840 5062352 61569.21 159840 5062352 61569.21 159840 5062352 61569.21 160023 5024546 52244.29 160023 5024546 52244.29 160023 5024546 52244.29 160023 5024546 52244.29 160023 5024546 52244.29 159669 5323292 50126.38 159669 5323292 50126.38 159669 5323292 50126.38 159669 5323292 50126.38 159669 5323292 50126.38 As you can see the query is partially working as needed, except Im getting duplicates for mgap_ska_id whereas it should be five individual mgap_ska_id numbers. and here is a sample of my data: mgap_ska_id account_manager_id mgap_growth mgap_recovery 5057810 64154 0 1160.78 5178114 24456 0 5773.42 5292421 160338 0 5146.04 5414091 24408 0 104.14 5057810 64154 0 1160.78 Can anyone see where Ive gone wrong in my query and how/where I might correct the error so I get the 5 top individual customers (mgap_ska_id) instead of the duplicated top single customer?

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  • Using Terminal Services 'query' in batch file

    - by dboarman-FissureStudios
    I have a batch file that checks several of our servers for a user. From the command: query user %userID% /server:ServerName I want to capture the output before it goes to the screen. Is there a way to redirect the output to a variable? The basic gist of what I want to accomplish is this - we iterate through our servers: query user %userID% /server:Server1 query user %userID% /server:Server2 query user %userID% /server:Server3 query user %userID% /server:Server4 Instead of outputting a message that the user could not be found on a specific server, I would like for it to only notify me if it finds the user on a server.

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  • Challenge 19 – An Explanation of a Query

    - by Dave Ballantyne
    I have received a number of requests for an explanation of my winning query of TSQL Challenge 19. This involved traversing a hierarchy of employees and rolling a count of orders from subordinates up to superiors. The first concept I shall address is the hierarchyId , which is constructed within the CTE called cteTree.   cteTree is a recursive cte that will expand the parent-child hierarchy of the personnel in the table @emp.  One useful feature with a recursive cte is that data can be ‘passed’ from the parent to the child data.  The hierarchyId column is similar to the hierarchyId data type that was introduced in SQL Server 2008 and represents the position of the person within the organisation. Let us start with a simplistic example Albert manages Bob and Eddie.  Bob manages Carl and Dave. The hierarchyId will represent each person’s position in this relationship in a single field.  In this simple example we could append the userID together into a varchar field as detailed below. This will enable us to select a branch of the tree by filtering using Where hierarchyId  ‘1,2%’ to select Bob and all his subordinates.  Naturally, this is not comprehensive enough to provide a full solution, but as opposed to concatenating the Id’s together into a varchar datatyped column, we can apply the same theory to a varbinary.  By CASTing the ID’s into a datatype of varbinary(4) ,4 is used as 4 bytes of data are used to store an integer and building a hierarchyId  from those.  For example: The important point to bear in mind for later in the query is that the binary data generated is 'byte order comparable'. ie We can ORDER a dataset with it and the resulting data, will be in the order required. Now, would probably be a good time to download the example file and, after the cte ‘cteTree’, uncomment the line ‘select * from cteTree’.  Mark this and all prior code and execute.  This will show you how this theory directly relates to the actual challenge data.  The only deviation from the above, is that instead of using the ID of an employee, I have used the row_number() ranking function to order each level by LastName,Firstname.  This enables me to order by the HierarchyId in the final result set so that the result set is in the required order. Your output should be something like the below.  Notice also the ‘Level’ Column that contains the depth that the employee is within the tree.  I would encourage you to ‘play’ with the query, change the order in the row_number() or the length of the cast in the hierarchyId to see how that effects the outcome.  The next cte, ‘cteTreeWithOrderCount’, is a join between cteTree and the @ord table, and COUNT’s the number of orders per employee.  A LEFT JOIN is employed here to account for the occasion where an employee has made no sales.   Executing a ‘Select * from cteTreeWithOrderCount’ will return the result set as below.  The order here is unimportant as this is only a staging point of the data and only the final result set in a cte chain needs an Order by clause, unless TOP is utilised. cteExplode joins the above result set to the tally table (Nums) for Level Occurances.  So, if level is 2 then 2 rows are required.  This is done to expand the dataset, to create a new column (PathInc), which is the (n+1) integers contained within the heirarchyid.  For example, with the data for Robert King as given above, the below 3 rows will be returned. From this you can see that the pathinc column now contains the values for Andrew Fuller and Steven Buchanan who are Robert King’s superiors within the tree.    Finally cteSumUp, sums the orders for each person and their subordinates using the PathInc generated above, and the final select does the final simple mathematics and filters to restrict the result set to only the ‘original’ row per employee.

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  • How To Publish Business Objects Query Service

    - by ssorrrell
    We are trying to copy a BO Query Service from one Universe to another. If you use the BO Query As A Service(QAAS) tool you can do this, but end up basically recreating the query service. It seems like the BusinessObjects.DSWS.* libraries allow you to read and write query services, but those don't appear in the QAAS tool. I think that those queries go into a different Universe than the QAAS tool pings. Perhaps there is a Universe for data and another for Web Service Queries. Monitoring the QAAS tool for HTTP traffic revealed that the BO Web Service used to run queries for the data they contain is also used to manage the Web Service queries. I was able to copy one Query Service into a new one in a new Universe using a Replace() on the XML string in QuerySpec to change the UniverseID. We can basically copy one Query Service to another Universe without manually rebuilding it except for one little thing. The QAAS tool includes a Publish button. This does something unknown, but important. Perhaps it makes some SOAP, WSDL or config files so that the copied Query Service is public. There doesn't seem to be any HTTP traffic to snoop on when it's doing this. The BusinessObjects.DSWS.* libraries include a Publish feature, but it's not for Query Services. It's for general files like Excel and PDF. Right now, we are relegated to using two tools. Does anyone know about how to Publish a BO Query Service programmatically just like the QAAS Tool?

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  • Query to find the data for every month of last year from the given date using mysql?

    - by Salil
    Hi All, I want data for the the last 1 year from the given date For ex:- I have date "2013-06-01" and i want data as follows also data i want is from three table using Group By or something else Month             Amount         Total_Data June 2013     100                5 May 2013       80                  4 -                     100                5 -                     100                5 July 2012       10                  2 I try following query but didn't workout SELECT DATE_FORMAT(rf.period, '%M %Y') as Month , sum(p.amount * ((100-q.amount)/100)) as Amount ,count(distinct q.label_id) as Total Data FROM table1 rf , table2 p , table3 q ,table4 a where rf.period BETWEEN '2013-06-01' AND '2013-06-01' and q.royalty_period BETWEEN '2013-06-01' AND '2013-06-01' and a.id = q.album_id and p.file_id = rf.id and p.upc = a.upc and p.local_revenue is not null GROUP BY Month Thanks in Advance, Salil Gaikwad

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  • Appengine datastore phantom entity - inconsistent state?

    - by aloo
    Getting a weird error on java appengine code that used to work fine (nothing has changed but the data in the datastore). I'm trying to iterate over the results of a query and change a few properties of the entities. The query does return a set of results, however, when I try to access the first result in the list, it throws an exception when trying to access any of its properties (but its key). Here's the exception: org.datanucleus.state.JDOStateManagerImpl isLoaded: Exception thrown by StateManager.isLoaded Could not retrieve entity of kind OnTheCan with key OnTheCan(3204258) org.datanucleus.exceptions.NucleusObjectNotFoundException: Could not retrieve entity of kind OnTheCan with key OnTheCan(3204258) at org.datanucleus.store.appengine.DatastoreExceptionTranslator.wrapEntityNotFoundException(DatastoreExceptionTranslator.java:60) And here is my code: PersistenceManager pm = PMF.get().getPersistenceManager(); Query query = null; List<OnTheCan> cans; query = pm.newQuery("SELECT this FROM " + OnTheCan.class.getName() + " WHERE open == true ORDER BY onTheCanId ASC"); query.setRange(0, num); cans = (List<OnTheCan>) query.execute(); for (OnTheCan c : cans) { System.err.println(c.getOnTheCanId()); // this works fine! getting the key works c.setOpen(false); // failure here with the above exception c.setAutoClosed(true); c.setEndTime(new Date(c.getStartTime().getTime() + 600000/*10*60*1000*/)); } pm.close(); The code throws the exception when trying to execute c.setOpen(false) - thats the first time I'm accessing or setting a property that isnt the key. So it seems there is a phantom entity in my datastore with key 3204258. THis entity doesn't really exist (queried the datastore from admin console) but for some reason its being returned by the query. Could my data store be in an inconsistent state? I've managed the following workaround by placing it as the first line in my for loop. Clearly an ugly hack: if (c.getOnTheCanId() == 3204258) { continue; } Any ideas?

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  • How can I get a distinct list of elements in a hierarchical query?

    - by RenderIn
    I have a database table, with people identified by a name, a job and a city. I have a second table that contains a hierarchical representation of every job in the company in every city. Suppose I have 3 people in the people table: [name(PK),title,city] Jim, Salesman, Houston Jane, Associate Marketer, Chicago Bill, Cashier, New York And I have thousands of job type/location combinations in the job table, a sample of which follow. You can see the hierarchical relationship since parent_title is a foreign key to title: [title,city,pay,parent_title] Salesman, Houston, $50000, CEO Cashier, Houston, $25000 CEO, USA, $1000000 Associate Marketer, Chicago, $75000 Senior Marketer, Chicago, $125000 ..... The problem I'm having is that my Person table is a composite key, so I don't know how to structure the start with part of my query so that it starts with each of the three jobs in the cities I specified. I can execute three separate queries to get what I want, but this doesn't scale well. e.g.: select * from jobs start with city = (select city from people where name = 'Bill') and title = (select title from people where name = 'Bill') connect by prior parent_title = title UNION select * from jobs start with city = (select city from people where name = 'Jim') and title = (select title from people where name = 'Jim') connect by prior parent_title = title UNION select * from jobs start with city = (select city from people where name = 'Jane') and title = (select title from people where name = 'Jane') connect by prior parent_title = title How else can I get a distinct list (or I could wrap it with a distinct if not possible) of all the jobs which are above the three people I specified?

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  • Bulk retrieval in HQL: could not execute native bulk manipulation query

    - by user179056
    Hello, We are getting a "could not execute native bulk manipulation query" error in HQL When we execute a query which is something like this. String query = "Select person.id from Person person where"; String bindParam = ""; List subLists = getChucnkedList(dd); for(int i = 0 ; i < subLists.size() ;i++){ bindParam = bindParam + " person.id in (:param" + i + ")"; if (i < subLists.size() - 1 ) { bindParam = bindParam + " OR " ; } } query = query + bindParam; final Query query1 = session.createQuery(query.toString()); for(int i = 0 ; i < subLists.size() ;i++){ query1.setParameterList("param" + i, subLists.get(i)); } List personIdsList = query1.list(); Basically to avoid the limit on IN clause in terms of number of ids which can be inserted (not more than 1000), we have created sublists of ids of not more than 1000 in number. We are using bind parameters to bind each sublist. However we still get error "could not execute native bulk manipulation query" How does one avoid the problem of limited parameters possible in IN query when parameters passed are more than 1000? regards Sameer

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  • How to combine a Distance and Keyword SQL query?

    - by Jason
    Hi Folks, I have a tables in my database called "points" and "category". A user will input info into both a location input and a keyword input text box. Then I want to find points in my table where the keyword matches either the "title" field in the points table, or the "category" but are within a certain distance from the user's location. I want to order the results by distance. Here are the 2 queries which btoh work independently: $mysql = "SELECT *, ( 3959 * acos( cos( radians('$search_lat') ) * cos( radians( lat ) ) * cos( radians( longi ) - radians('$search_lng') ) + sin( radians('$search_lat') ) * sin( radians( lat ) ) ) ) AS distance FROM points HAVING distance < '$radius'"; $mysql2 = "SELECT * FROM `points` LEFT JOIN category USING ( category_id ) WHERE (point_title LIKE '%$esc_catsearch%' OR category.title LIKE '%$esc_catsearch%')"; Here is what I tried: $sql_search = sprintf("SELECT *,point_id FROM points WHERE point_title LIKE '%%%s%%' UNION SELECT *, ( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( longi ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance FROM points HAVING distance < '%s' ORDER BY distance LIMIT %d , %d", $esc_catsearch, mysql_real_escape_string($search_lat), mysql_real_escape_string($search_lng), mysql_real_escape_string($search_lat), mysql_real_escape_string($radius), $offset, $rowsPerPage); But it tells me there is no know column "distance". If I remove the "Order By" phrase then it works but I'm still not sure this is giving me the results I want. I also tried the query the other way around with the distance search first but that seems to ignore my keyword. Any thoughts would be much appreciated!

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  • Codeigniter Pagination: Run the Query Twice?

    - by Frank
    I'm using codeigniter and the pagination class. This is such a basic question, but I need to make sure I'm not missing something. In order to get the config items necessary to paginate results getting them from a MySQL database it's basically necessary to run the query twice is that right? In other words, you have to run the query to determine the total number of records before you can paginate. So I'm doing it like: Do this query to get number of results $this->db->where('something', $something); $query = $this->db->get('the_table_name'); $num_rows = $query->num_rows(); Then I'll have to do it again to get the results with the limit and offset. Something like: $this->db->where('something', $something); $this->db->limit($limit, $offset); $query = $this->db->get('the_table_name'); if($query->num_rows()){ foreach($query->result_array() as $row){ ## get the results here } } I just wonder if I'm actually doing this right in that the query always needs to be run twice? The queries I'm using are much more complex than what is shown above.

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  • Query Level 2 Caching throwing ClassCastException

    - by Sameer Malhotra
    Hi, I am using JPA and Hibernate for the database. I have configured (EHCacache) second level cache and query level cache, but just to make sure that caching is working I was trying to get the statistics which is throwing class cast exception.Any help will be highly appreciated. My main goal is to see all the objects which have been cached to make sure that the caching is working properly. Here is the code: public List<CodeValue> findByCodetype(String propertyName) { try { final String queryString = "select model from CodeValue model where model.codetype" + "= :propertyValue" + " order by model.code"; Query query = em.createQuery(queryString); query.setHint("org.hibernate.cacheable", true); query.setHint("org.hibernate.cacheRegion", "query.findByCodetype"); query.setParameter("propertyValue", propertyName); List resultList = query.getResultList(); org.hibernate.Session session = (Session) em.getDelegate(); SessionFactory sessionFactory = session.getSessionFactory(); Map cacheEntries = sessionFactory.getStatistics() .getSecondLevelCacheStatistics("query.findByCodetype") .getEntries(); logger.info("The statistics are: " + cacheEntries); return resultList; } catch (RuntimeException re) { logger.error("findByCodetype failed in trauma patient", re); throw re; } } The error is existing right when I am trying to print the statistics. Below is exception: [6/7/10 19:23:17:059 GMT] 00000034 SystemOut O java.lang.ClassCastException: org.hibernate.cache.QueryKey incompatible with org.hibernate.cache.CacheKey at org.hibernate.stat.SecondLevelCacheStatistics.getEntries(SecondLevelCacheStatistics.java:51) at com.idph.trauma.registry.service.TraumaPatientDAO.findByCodetype(TraumaPatientDAO.java:439) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:615) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204) at $Proxy209.findByCodetype(Unknown Source) Do you know what's going on?

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  • MySQL Gurus: How to pull a complex grid of data from MySQL database with one query?

    - by iopener
    Hopefully this is less complex than I think. I have one table of companies, and another table of jobs, and a third table with that contains a single entry for each employee in each job from each company. NOTE: Some companies won't have employees in some jobs, and some companies will have more than one employee in some jobs. The company table has a companyid and companyname field, the job table has a jobid and jobtitle field, and the employee table has employeeid, companyid, jobid and employeename fields. I want to build a table like this: +-----------+-----------+-----------+ | Company A | Company B | Company C | ------+-----------+-----------+-----------+ Job A | Emp 1 | Emp 2 | | ------+-----------+-----------+-----------+ Job B | Emp 3 | | Emp 4 | | | | Emp 5 | ------+-----------+-----------+-----------+ Job C | | Emp 6 | | | | Emp 7 | | | | Emp 8 | | ------+-----------+-----------+-----------+ I had previously been looping through a result set of jobs, and for each job, looping through a result set of each company, and for each company, looping through each employee and printing it in a table (gross, but performance was not supposed to be a consideration). The app has grown in popularity, and now we have 100 companies and hundreds of jobs, and the server is crapping out (all the id fields are indexed). Any suggestions on how to write a single query to get this data? I don't need the company names or job titles (obviously), but I do need some way to identify where each row from the result should be printed. I'm imagining a result set that just contained a long list of joined employees, and I could write a loop to use the companyid and employeeid values to tell me when to create a new cell or table row. This works as long as there aren't ZERO employees; I would need a NULL employee name for that I think? Am I completely on the wrong track? Thanks in advance for any ideas!

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  • How can i get rid of 'ORA-01489: result of string concatenation is too long' in this query?

    - by core_pro
    this query gets the dominating sets in a network. so for example given a network A<----->B B<----->C B<----->D C<----->E D<----->C D<----->E F<----->E it returns B,E B,F A,E but it doesn't work for large data because i'm using string methods in my result. i have been trying to remove the string methods and return a view or something but to no avail With t as (select 'A' as per1, 'B' as per2 from dual union all select 'B','C' from dual union all select 'B','D' from dual union all select 'C','B' from dual union all select 'C','E' from dual union all select 'D','C' from dual union all select 'D','E' from dual union all select 'E','C' from dual union all select 'E','D' from dual union all select 'F','E' from dual) ,t2 as (select distinct least(per1, per2) as per1, greatest(per1, per2) as per2 from t union select distinct greatest(per1, per2) as per1, least(per1, per2) as per1 from t) ,t3 as (select per1, per2, row_number() over (partition by per1 order by per2) as rn from t2) ,people as (select per, row_number() over (order by per) rn from (select distinct per1 as per from t union select distinct per2 from t) ) ,comb as (select sys_connect_by_path(per,',')||',' as p from people connect by rn > prior rn ) ,find as (select p, per2, count(*) over (partition by p) as cnt from ( select distinct comb.p, t3.per2 from comb, t3 where instr(comb.p, ','||t3.per1||',') > 0 or instr(comb.p, ','||t3.per2||',') > 0 ) ) ,rnk as (select p, rank() over (order by length(p)) as rnk from find where cnt = (select count(*) from people) order by rnk ) select distinct trim(',' from p) as p from rnk where rnk.rnk = 1`

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  • World's Most Challening MySQL SQL Query (least I think so...)

    - by keruilin
    Whoever answers this question can claim credit for solving the world's most challenging SQL query, according to yours truly. Working with 3 tables: users, badges, awards. Relationships: user has many awards; award belongs to user; badge has many awards; award belongs to badge. So badge_id and user_id are foreign keys in the awards table. The business logic at work here is that every time a user wins a badge, he/she receives it as an award. A user can be awarded the same badge multiple times. Each badge is assigned a designated point value (point_value is a field in the badges table). For example, BadgeA can be worth 500 Points, BadgeB 1000 Points, and so on. As further example, let's say UserX won BadgeA 10 times and BadgeB 5 times. BadgeA being worth 500 Points, and BadgeB being worth 1000 Points, UserX has accumulated a total of 10,000 Points ((10 x 500) + (5 x 1000)). The end game here is to return a list of top 50 users who have accumulated the most badge points. Can you do it?

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  • How does C#'s DateTime.Now affect query plan caching in SQL Server?

    - by Bill Paetzke
    Given: Let's say we have a stored procedure. It reports data back to a user on a webpage. The user can set a date range. If the user sets today's date as the "end date," which includes today's data, the web app passes DateTime.Now to the sql proc. Let's say that one user runs a report--5/1/2010 to now--over and over several times. On the webpage, the user sees "5/1/2010" to "5/4/2010." But the web app passes DateTime.Now to the sql proc as the end date. So, the end date in the proc will always be different, although the user is querying a similar date range. Assume the number of records in the table and number of users are large. So any performance gains matter. Hence the importance of the question. Question: Does passing DateTime.Now as a parameter to a proc prevent SQL Server from caching the query plan? If so, then is the web app missing out on huge performance gains? Possible Solution: I thought DateTime.Today.AddDays(1) would be a possible solution. It would allow the user to get the latest data and always pass the same end date to the sql proc--"5/5/2010" in this case. Please speak to this as well. Sample proc and execution (if that helps to understand): CREATE PROCEDURE GetFooData @StartDate datetime @EndDate datetime AS SELECT * FROM Foo WHERE LogDate >= @StartDate AND LogDate < @EndDate Here's a sample execution using DateTime.Now: EXEC GetFooData '2010-05-01', '2010-05-04 15:41:27' -- passed in DateTime.Now Here's a sample execution using DateTime.Today.AddDays(1) EXEC GetFooData '2010-05-01', '2010-05-05' -- passed in DateTime.Today.AddDays(1) The same data is returned for both procs, since the current time is: 2010-05-04 15:41:27.

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  • Delaying LINQ to SQL Select Query Execution

    - by Maxim Z.
    I'm building an ASP.NET MVC site that uses LINQ to SQL. In my search method that has some required and some optional parameters, I want to build a LINQ query while testing for the existence of those optional parameters. Here's what I'm currently thinking: using(var db = new DBDataContext()) { IQueryable<Listing> query = null; //Handle required parameter query = db.Listings.Where(l => l.Lat >= form.bounds.extent1.latitude && l.Lat <= form.bounds.extent2.latitude); //Handle optional parameter if (numStars != null) query = query.Where(l => l.Stars == (int)numStars); //Other parameters... //Execute query (does this happen here?) var result = query.ToList(); //Process query... Will this implementation "bundle" the where clauses and then execute the bundled query? If not, how should I implement this feature? Also, is there anything else that I can improve? Thanks in advance.

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  • query structure - ignoring entries for the same event from multiple users?

    - by Andrew Heath
    One table in my MySQL database tracks game plays. It has the following structure: SCENARIO_VICTORIES [ID] [scenario_id] [game] [timestamp] [user_id] [winning_side] [play_date] ID is the autoincremented primary key. timestamp records the moment of submission for the record. winning_side has one of three possible values: 1, 2, or 0 (meaning a draw) One of the queries done on this table calculates the victory percentage for each scenario, when that scenario's page is viewed. The output is expressed as: Side 1 win % Side 2 win % Draw % and queried with: SELECT winning_side, COUNT(scenario_id) FROM scenario_victories WHERE scenario_id='$scenID' GROUP BY winning_side ORDER BY winning_side ASC and then processed into the percentages and such. Sorry for the long setup. My problem is this: several of my users play each other, and record their mutual results. So these battles are being doubly represented in the victory percentages and result counts. Though this happens infrequently, the userbase isn't large and the double entries do have a noticeable effect on the data. Given the table and query above - does anyone have any suggestions for how I can "collapse" records that have the same play_date & game & scenario_id & winning_side so that they're only counted once?

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  • How does DateTime.Now affect query plan caching in SQL Server?

    - by Bill Paetzke
    Question: Does passing DateTime.Now as a parameter to a proc prevent SQL Server from caching the query plan? If so, then is the web app missing out on huge performance gains? Possible Solution: I thought DateTime.Today.AddDays(1) would be a possible solution. It would pass the same end-date to the sql proc (per day). And the user would still get the latest data. Please speak to this as well. Given Example: Let's say we have a stored procedure. It reports data back to a user on a webpage. The user can set a date range. If the user sets today's date as the "end date," which includes today's data, the web app passes DateTime.Now to the sql proc. Let's say that one user runs a report--5/1/2010 to now--over and over several times. On the webpage, the user sees 5/1/2010 to 5/4/2010. But the web app passes DateTime.Now to the sql proc as the end date. So, the end date in the proc will always be different, although the user is querying a similar date range. Assume the number of records in the table and number of users are large. So any performance gains matter. Hence the importance of the question. Example proc and execution (if that helps to understand): CREATE PROCEDURE GetFooData @StartDate datetime @EndDate datetime AS SELECT * FROM Foo WHERE LogDate >= @StartDate AND LogDate < @EndDate Here's a sample execution using DateTime.Now: EXEC GetFooData '2010-05-01', '2010-05-04 15:41:27' -- passed in DateTime.Now Here's a sample execution using DateTime.Today.AddDays(1) EXEC GetFooData '2010-05-01', '2010-05-05' -- passed in DateTime.Today.AddDays(1) The same data is returned for both procs, since the current time is: 2010-05-04 15:41:27.

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  • How should I name my SQL query files? Should I use some methodology?

    - by Mehper C. Palavuzlar
    We have an Oracle 10g database (a huge one) in our company, and I provide employees with data upon their requests. My problem is, I save almost every SQL query I wrote, and now my list has grown too much. I want to organize and rename these .sql files so that I can find the one I want easily. At the moment, I'm using some folders named as Sales Dept, Field Team, Planning Dept, Special etc. and under those folders there are .sql files like Delivery_sales_1, Delivery_sales_2, ... Sent_sold_lostsales_endpoints, ... Sales_provinces_period, Returnrates_regions_bymonths, ... Jack_1, Steve_1, Steve_2, ... I try to name the files regarding their content but this makes file names longer and does not completely meet my needs. Sometimes someone comes and demands a special report, and I give the file his name, but this is also not so good. I know duplicates or very similar files are growing in time but I don't have control over them. Can you show me the right direction to rename all these files and folders and organize my queries for easy and better control? TIA.

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  • Why can't you return a List from a Compiled Query?

    - by Andrew
    I was speeding up my app by using compiled queries for queries which were getting hit over and over. I tried to implement it like this: Function Select(ByVal fk_id As Integer) As List(SomeEntity) Using db As New DataContext() db.ObjectTrackingEnabled = False Return CompiledSelect(db, fk_id) End Using End Function Shared CompiledSelect As Func(Of DataContext, Integer, List(Of SomeEntity)) = _ CompiledQuery.Compile(Function(db As DataContext, fk_id As Integer) _ (From u In db.SomeEntities _ Where u.SomeLinkedEntity.ID = fk_id _ Select u).ToList()) This did not work and I got this error message: Type : System.ArgumentNullException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 Message : Value cannot be null. Parameter name: value However, when I changed my compiled query to return IQueryable instead of List like so: Function Select(ByVal fk_id As Integer) As List(SomeEntity) Using db As New DataContext() db.ObjectTrackingEnabled = False Return CompiledSelect(db, fk_id).ToList() End Using End Function Shared CompiledSelect As Func(Of DataContext, Integer, IQueryable(Of SomeEntity)) = _ CompiledQuery.Compile(Function(db As DataContext, fk_id As Integer) _ From u In db.SomeEntities _ Where u.SomeLinkedEntity.ID = fk_id _ Select u) It worked fine. Can anyone shed any light as to why this is? BTW, compiled queries rock! They sped up my app by a factor of 2.

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  • Using a variable in a mysql query, in a C++ MFC program.

    - by D.Gaughan
    Hi, after extensive trawling of the internet I still havent found any solution for this problem. I`m writing a small C++ app that connects to an online database and outputs the data in a listbox. I need to enable a search function using an edit box, but I cant get the query to work while using a variable. My code is: res = mysql_perform_query (conn, "select distinct artist from Artists"); //res = mysql_perform_query (conn, "select album from Artists where artist = ' ' "); while((row = mysql_fetch_row(res)) != NULL){ CString str; UpdateData(); str = ("%s\n", row[0]); UpdateData(FALSE); m_list_control.AddString(str); } the first "res = " line is working fine, but I need the second one to work. I have a member variable m_search_edit set up for the edit box, but any way I try to include it in the sql statement causes errors. eg. res = mysql_perform_query (conn, "select album from Artists where artist = '"+m_search_edit+" ' "); causes this error: error C2664: 'mysql_perform_query' : cannot convert parameter 2 from 'class CString' to 'char *' No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called" And when I convert m_search_edit to a char* it gives me a " Cannot add 2 pointers" error. Any way around this???

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  • In sync query calls, one query causing other query to run slower. Why?

    - by Irchi
    Sorry for the long question, but I think this is an interesting situation and I couldn't find any explanations for it: I was involved in optimization of an application that performed a large number of sequential SELECT and INSERT statements on a single dedicated SQL Server database. The process needs to INSERT a large number of records into a table, but for each of them there should be some value mappings, which performed using SELECT statements on another table in the same database. For a specific execution, it took 90 minutes to run. I used a profiler (JProfiler - the application is Java-based) to determine how much time does each part of the application take. It yields that 60% of the time was spent on INSERT method calls, and almost 20% on SELECT calls (the rest distributed in other parts). After some trials, I came to this situation: I commented out the INSERT query that took 60% of the time. I was expecting for the total run time to be around 35 minutes, as I have removed 60% of the 90 minutes. But the whole process took the same 90 minutes (doing only SELECTs and nothing else), but each SELECT took longer this time! Everything was running sync, there were no async calls. And there was only one single thread of execution. SELECT and INSERT queries are very simple, and don't have anything special, and they are on different tables, but on the same DB. I tested with both the DB on the application machine, and on a remote network machine. I can't think of any explanation for this, as the Profiler (Application profiler, not SQL Profiler) reported the changes in the method call times, and by removing INSERT statements SELECT statements took longer to run. Can anyone give me some kind of explanation of what could have happened? (there can't be cache / query optimization stuff, because the queries were run in sync, and in a single thread, and it was far from affecting the cache this much) I should note that the bottleneck of the speed was in SQL server, using most of the CPU time.

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  • SQL SERVER – Developer Training Resources and Summary Roundup

    - by pinaldave
    It is always pleasure for any author when other renowned authors in the industry write about you. Earlier I wrote a five part blog series on Developer Training and I have received a phenomenal response to the series. I have received plenty of comments, questions and feedback. I thought it would be nice to sum up the whole series as well answer a few of the questions received. Quick Recap Developer Training - Importance and Significance - Part 1 In this part we discussed the importance of training in the real world. The most important and valuable resource any company is its employee. Employees who have been well-trained will be better at their jobs and produce a better product.  An employee who is well trained obviously knows more about their job and all the technical aspects. I have a very high opinion about training employees and it is the most important task. Developer Training – Employee Morals and Ethics – Part 2 In this part we discussed the most crucial components of training. Often employees are expecting the company to pay for their training and the company expresses no interest in training the employee. Quite often training expenses are the real issue for both the employee and employer. There are companies that pay for 100% of the expenses and there are employees who opt for training on their own expense during their personal time. Training is often looked at as vacation by employee and employers and we need to change this mind-set. One of the ways is to report back the learning to your manager and implement newly learned knowledge in day-to-day work. Developer Training – Difficult Questions and Alternative Perspective - Part 3 This part was the most difficult to write as I tried to address a few difficult questions and answers. Training is such a sensitive issue that many developers when not receiving chance for training think about leaving the organization. The manager often feels pressure to accommodate every single employee for training even though his training budget is limited. It is indeed the responsibility of the developer to get maximum advantage from the training. Training immediately helps organizations but stays as a part of an employee’s knowledge forever. Developer Training – Various Options for Developer Training – Part 4 In this part I tried to explore a few methods and options for training. The generic feedback I received on this blog post was short and I should have explored each of the subject of the training in details. I believe there are two big buckets of training 1) Instructor Lead Training and 2) Self Lead Training. The common element between both the methods is “learning material”. Learning material can be of any format – videos, books, paper notes or just a plain black board. Instructor-led training is a very effective mode but not possible every single time. During the course of the developer’s career, one has to learn lots of new technology and it is almost impossible to have a quality trainer available on that subject at that time. Books are most effective and proven methods, however, it always helps if someone explains the concepts of the book with a demonstration. In recent times I have started to believe in online trainings which leads to a hybrid experience. Online trainings take the best part of the books and the best part of the instructor-led training and gives effective training in a matter of hours. Developer Training – A Conclusive Summary- Part 5 In this part, I shared what I was continuously thinking about developer training. There is no better teacher than oneself. There is no better motivation than a personal desire to learn new technology. Honestly there is nothing more personal learning. That “change is the only constant” and “adapt & overcome” are the essential lessons of life. One cannot stop the learning and resist the change. In the IT industry “ego of knowing all” and the “resistance to change” are the most challenging issues. Once someone overcomes them, life is much easier. I believe that proper and appropriate high quality training can help to address the burning issues. Opinion of Friends I invited a few of my friends to express their opinion about developer training and here are their opinions. I am listing them here in the order of the blog post publishing date. Nakul Vachhrajani - Developer Trainings-Importance, Benefits, Tips and follow-up Nakul’s sums of many of the concepts which are complementary to my blog posts. Nakul addresses the burning question of developer training with different angles. I am personally very impressed by his following statement - “Being skilled does not mean having just a stack of certifications, but it also means having an understanding about the internals of the products that you are working on – and using that knowledge to improve the efficiency & productivity at the workplace in turn resulting in better products, better consulting abilities and a happier self.” Nakul also suggests the online training options of Pluralsight. Vinod Kumar - Training–a necessity or bonus Vinod Kumar comes up with excellent follow up on developer training. Vinod is known for his inspirational writing about SQL Server. Vinod starts with a story of a student who is extremely eager to learn the wisdom of life from a monk but the monk does not accept him as a disciple for a long time. The conversation between student and monk is indeed an essence of all learning. We all want to learn quickly and be successful but the most important thing in life is to have the right attitude towards learning and more so towards life. The blog post end with a very important thought about how to avoid the famous excuse – “I don’t have enough time.” Ritesh Shah - Training – useful or useless? Ritesh brings up very important concept related to training. Ritesh in his meticulous style explains why training is an important and lifelong process. Training must not stop at any age but should continue forever. The moment training stops, progress stops along with. Paras Doshi - Professional Development Resource Paras is known for his to–the-point writing, and has summarized the five part series very precisely. He read the five part series and created a digest summary of the blog post. If you are in a rush and have no time to read my five series – I suggest you read his blog post. Training Resources I am often asked what the best resources for learning new technology are. This is the most difficult question EVER. There are plenty of good training resources available. When it is about training our needs are different, our preference of learning is different and we all have an opinion. Additionally, we all are located in different geographic locations worldwide and there is no way one solution will fit all. However, let me list a few of the training resources which I have built so far and you can consume them if you find it relevant to your need. SQL Server Books SQL Server Interview Questions and Answers SQL Wait Stats SQL Programming Joes 2 Pros SQL Server Video Tutorials SQL Server Questions and Answers SQL Server Performance: Indexing Basics SQL Server Performance: Introduction to Query Tuning SQL in Sixty Seconds Series of Sixty Seconds Learning Video on YouTube Trust me worldwide web is very big and there are plenty of high quality learning materials available worldwide – trainer-led as well online. I suggest you explore various options and make the best choice for yourself. Remember, training is your personal journey and it should never stop. Are you ready? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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