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  • Question about Benchmark funcion in Mysql ( Incredible results ).

    - by xRobot
    I have 2 tables: author with 3 millions of rows. book with 20 miles rows. . So I have benchmarked this query with a join: SELECT BENCHMARK(100000000, 'SELECT book.title, author.name FROM `book` , `author` WHERE book.id = author.book_id ') And this is the result: Query took 0.7438 sec ONLY 0.7438 seconds for 100 millions of query with a join ??? Do I make some mistakes or this is the right result ?

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  • Time diff calculations where date and time are in seperate columns

    - by pedalpete
    I've got a query where I'm trying to get the hours in duration (eg 6.5 hours) between two different times. In my database, time and date are held in different fields so I can efficiently query on just a startDate, or endDate as I never query specifically on time. My query looks like this SELECT COUNT(*), IFNULL(SUM(TIMEDIFF(endTime,startTime)),0) FROM events WHERE user=18 Sometimes an event will go overnight, so the difference between times needs to take into account the differences between the dates as well. I've been trying SELECT COUNT(*), IFNULL(SUM(TIMEDIFF(CONCAT(endDate,' ',endTime),CONCAT(startDate,' ',startTime))),0) FROM events WHERE user=18 Unfortunately I only get errors when I do this, and I can't seem to combine the two fields into a single timestamp.

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  • Cost of logic in a query

    - by FrustratedWithFormsDesigner
    I have a query that looks something like this: select xmlelement("rootNode", (case when XH.ID is not null then xmlelement("xhID", XH.ID) else xmlelement("xhID", xmlattributes('true' AS "xsi:nil"), XH.ID) end), (case when XH.SER_NUM is not null then xmlelement("serialNumber", XH.SER_NUM) else xmlelement("serialNumber", xmlattributes('true' AS "xsi:nil"), XH.SER_NUM) end), /*repeat this pattern for many more columns from the same table...*/ FROM XH WHERE XH.ID = 'SOMETHINGOROTHER' It's ugly and I don't like it, and it is also the slowest executing query (there are others of similar form, but much smaller and they aren't causing any major problems - yet). Maintenance is relatively easy as this is mostly a generated query, but my concern now is for performance. I am wondering how much of an overhead there is for all of these case expressions. To see if there was any difference, I wrote another version of this query as: select xmlelement("rootNode", xmlforest(XH.ID, XH.SER_NUM,... (I know that this query does not produce exactly the same, thing, my plan was to move the logic to PL/SQL or XSL) I tried to get execution plans for both versions, but they are the same. I'm guessing that the logic does not get factored into the execution plan. My gut tells me the second version should execute faster, but I'd like some way to prove that (other than writing a PL/SQL test function with timing statements before and after the query and running that code over and over again to get a test sample). Is it possible to get a good idea of how much the case-when will cost? Also, I could write the case-when using the decode function instead. Would that perform better (than case-statements)?

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  • SQL Server Querying An XML Field

    - by Gavin Draper
    I have a table that contains some meta data in an XML field. For example <Meta> <From>[email protected]</From> <To> <Address>[email protected]</Address> <Address>[email protected]</Address> </To> <Subject>ESubject Goes Here</Subject> </Meta> I want to then be able to query this field to return the following results From To Subject [email protected] [email protected] Subject Goes Here [email protected] [email protected] Subject Goes Here I've written the following query SELECT MetaData.query('data(/Meta/From)') AS [From], MetaData.query('data(/Meta/To/Address)') AS [To], MetaData.query('data(/Meta/Subject)') AS [Subject] FROM Documents However this only returns one record for that XML field. It combines both the 2 addresses into one result. Is it possible for split these on to separate records? The result I'm getting is From To Subject [email protected] [email protected] [email protected] Subject Goes Here Thanks Gav

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  • Dates that intersect

    - by MikeAbyss
    Hi everyone, I've been researching this problem for awhile now and I can't seem to come to a solution, hopefully someone here can help. Currently I'm working with Microsoft SQL server management, I've been trying to do the following: Previously, the old query would just return the results that fit between two dates Heres the previous query: SELECT e.Name, o.StartDate, o.EndDate FROM dbo.Name e, dbo.Date o WHERE where e.Name = o.Name and o.StartDate <= '2010-09-28 23:59:59' and o.EndDate >= '2010-9-28 00:00:00' and e.Name like 'A' Example table that is produced after the query runs (The real table has a lot more rows obviously :P) : Name Start End A 2010-09-28 07:00:00 2010-09-28 17:00:00 A 2010-09-28 13:45:00 2010-09-28 18:00:00 A 2010-09-28 08:00:00 2010-09-28 16:00:00 A 2010-09-28 07:00:00 2010-09-28 15:30:00 However we need to change this, so that the query does the following: find the dates that intersect for a day x find the dates that don't intersect for a day x I've found a real useful site regarding this http://bloggingabout.net/blogs/egiardina/archive/2008/01/30/check-intersection-of-two-date-ranges-in-sql.aspx However the date to compare against is inputted, mine on the other hand has to all dates that intersect/don't intersect. Thanks for the help everyone.

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  • Question about Benchmark function in Mysql ( Incredible results ).

    - by xRobot
    I have 2 tables: author with 3 millions of rows. book with 20 miles rows. . So I have benchmarked this query with a join: SELECT BENCHMARK(100000000, 'SELECT book.title, author.name FROM `book` , `author` WHERE book.id = author.book_id ') And this is the result: Query took 0.7438 sec ONLY 0.7438 seconds for 100 millions of query with a join ??? Do I make some mistakes or this is the right result ?

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  • MySQL Update query with left join and group by

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

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  • SQL RDBMS : one query or multiple calls

    - by None None
    After looking around the internet, I decided to create DAOs that returned objects (POJOs) to the calling business logic function/method. For example: a Customer object with a Address reference would be split in the RDBMS into two tables; Customer and ADDRESS. The CustomerDAO would be in charge of joining the data from the two tables and create both an Address POJO and Customer POJO adding the address to the customer object. Finally return the fulll Customer POJO. Simple, however, now i am at a point where i need to join three or four tables and each representing an attribute or list of attributes for the resulting POJO. The sql will include a group by but i will still result with multiple rows for the same pojo, because some of the tables are joining a one to many relationship. My app code will now have to loop through all the rows trying to figure out if the rows are the same with different attributes or if the record should be a new POJO. Should I continue to create my daos using this technique or break up my Pojo creation into multiple db calls to make the code easier to understand and maintain?

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  • mysql join with conditional

    - by Conor H
    Hi There, I am currently working on a MySQL query that contains a table: TBL:lesson_fee -fee_type_id (PRI) -lesson_type_id (PRI) -lesson_fee_amount this table contains the fees for a particular 'lesson type' and there are different 'fee names' (fee_type). Which means that there can be many entries in this table for one 'lesson type' In my query I am joining this table onto the rest of the query via the 'lesson_type' table using: lesson_fee INNER JOIN (other joins here) ON lesson_fee.lesson_type_id = lesson_type.lesson_type_id The problem with this is that it is currently returning duplicate data in the result. 1 row for every duplicate entry in the 'lesson fee' table. I am also joining the 'fee type' table using this 'fee_type_id' Is there a way of telling MySQL to say "Join the lesson_fee table rows that have lesson_fee.lesson_type_id and fee_type_id = client.fee_type_id". UPDATE: Query: SELECT lesson_booking.lesson_booking_id,lesson_fee.lesson_fee_amount FROM fee_type INNER JOIN (lesson_fee INNER JOIN (color_code INNER JOIN (employee INNER JOIN (horse_owned INNER JOIN (lesson_type INNER JOIN (timetable INNER JOIN (lesson_booking INNER JOIN CLIENT ON client.client_id = lesson_booking.client_id) ON lesson_booking.timetable_id = timetable.timetable_id) ON lesson_type.lesson_type_id = timetable.lesson_type_id) ON horse_owned.horse_owned_id = lesson_booking.horse_owned_id) ON employee.employee_id = timetable.employee_id) ON employee.color_code_id = color_code.color_code_id) ON lesson_fee.lesson_type_id = lesson_type.lesson_type_id) ON lesson_fee.fee_type_id = client.fee_type_id WHERE booking_date = '2010-04-06' ORDER BY lesson_booking_id ASC How do I keep the format(indentation) of my query?

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  • MySql mutliple tables

    - by Chris Harrison
    I've been looking into JOIN, subqueries and other ways of doing this, but I can't work out the best way to do this is... I have a table (ps_category_product): id_product, id_category I want to perform a query on it like: SELECT id_product FROM ps_category_product WHERE id_category='$this_cat' BUT, I only want to perform this query where the ID's are returned by a query on another table (ps_product): id_product, active SELECT id_product FROM ps_product WHERE active='1' Can anyone help me with getting these two queries working together?

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  • Creating ASP.NET 3.5 Admin Pages using a Query String in a Master Page

    This is the continuation of part one which ran on Tuesday of last week. After deleting the styles lt style type= text css gt in the head section of MasterPage.master you will need to create an external CSS to solve the relative URL problems in the website. This will ensure that the background images and links work according to the master page design. This article will explain how to do this and more.... Comcast? Business Class - Official Site Learn About Comcast Small Business Services. Best in Phone, TV & Internet.

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  • sql select from a large number of IDs

    - by Claudiu
    I have a table, Foo. I run a query on Foo to get the ids from a subset of Foo. I then want to run a more complicated set of queries, but only on those IDs. Is there an efficient way to do this? The best I can think of is creating a query such as: SELECT ... --complicated stuff WHERE ... --more stuff AND id IN (1, 2, 3, 9, 413, 4324, ..., 939393) That is, I construct a huge "IN" clause. Is this efficient? Is there a more efficient way of doing this, or is the only way to JOIN with the inital query that gets the IDs? If it helps, I'm using SQLObject to connect to a PostgreSQL database, and I have access to the cursor that executed the query to get all the IDs.

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  • SSMS: The Query Window Keyboard Shortcuts

    Simple-Talk's free wallchart of the most important SSMS keyboard shortcuts aims to help find all those curiously forgettable key combinations within SQL Server Management Studio that unlock the hidden magic that is available for editing and executing queries. The Future of SQL Server MonitoringMonitor wherever, whenever with Red Gate's SQL Monitor. See it live in action now.

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  • OperationalError "unable to open database file" processing query results with SQLAlchemy and SQLite3

    - by Peter
    I'm running into this little problem that I hope is just a dumb user error. It looks like some sort of a size limit with a query to a SQLite database. I managed to reproduce the issue with an in-memory DB and a simple script shown below. I can make it work by either reducing the number of records in the DB; or by reducing the size of each record; or by dropping the order_by() call. I am using Python 2.5.5 and SQLAlchemy 0.6.0 in a Cygwin environment. Thanks! #!/usr/bin/python from sqlalchemy.orm import sessionmaker import sqlalchemy import sqlalchemy.orm class Person(object): def __init__(self, name): self.name = name engine = sqlalchemy.create_engine('sqlite:///:memory:') Session = sessionmaker(bind=engine) metadata = sqlalchemy.schema.MetaData(bind=engine) person_table = sqlalchemy.Table('person', metadata, sqlalchemy.Column('id', sqlalchemy.types.Integer, primary_key=True), sqlalchemy.Column('name', sqlalchemy.types.String)) metadata.create_all(engine) sqlalchemy.orm.mapper(Person, person_table) session = Session() session.add_all([Person("012345678901234567890123456789012") for i in range(5000)]) session.commit() persons = session.query(Person).order_by(Person.name).all() print "count =", len(persons) session.close() The all() call to the query result fails with the OperationalError exception: Traceback (most recent call last): File "./stress.py", line 27, in <module> persons = session.query(Person).order_by(Person.name).all() File "/usr/lib/python2.5/site-packages/sqlalchemy/orm/query.py", line 1343, in all return list(self) File "/usr/lib/python2.5/site-packages/sqlalchemy/orm/query.py", line 1451, in __iter__ return self._execute_and_instances(context) File "/usr/lib/python2.5/site-packages/sqlalchemy/orm/query.py", line 1456, in _execute_and_instances mapper=self._mapper_zero_or_none()) File "/usr/lib/python2.5/site-packages/sqlalchemy/orm/session.py", line 737, in execute clause, params or {}) File "/usr/lib/python2.5/site-packages/sqlalchemy/engine/base.py", line 1109, in execute return Connection.executors[c](self, object, multiparams, params) File "/usr/lib/python2.5/site-packages/sqlalchemy/engine/base.py", line 1186, in _execute_clauseelement return self.__execute_context(context) File "/usr/lib/python2.5/site-packages/sqlalchemy/engine/base.py", line 1215, in __execute_context context.parameters[0], context=context) File "/usr/lib/python2.5/site-packages/sqlalchemy/engine/base.py", line 1284, in _cursor_execute self._handle_dbapi_exception(e, statement, parameters, cursor, context) File "/usr/lib/python2.5/site-packages/sqlalchemy/engine/base.py", line 1282, in _cursor_execute self.dialect.do_execute(cursor, statement, parameters, context=context) File "/usr/lib/python2.5/site-packages/sqlalchemy/engine/default.py", line 277, in do_execute cursor.execute(statement, parameters) sqlalchemy.exc.OperationalError: (OperationalError) unable to open database file u'SELECT person.id AS person_id, person.name AS person_name \nFROM person ORDER BY person.name' ()

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  • NHibernate (3.1.0.4000) NullReferenceException using Query<> and NHibernate Facility

    - by TigerShark
    I have a problem with NHibernate, I can't seem to find any solution for. In my project I have a simple entity (Batch), but whenever I try and run the following test, I get an exception. I've triede a couple of different ways to perform a similar query, but almost identical exception for all (it differs in which LINQ method being executed). The first test: [Test] public void QueryLatestBatch() { using (var session = SessionManager.OpenSession()) { var batch = session.Query<Batch>() .FirstOrDefault(); Assert.That(batch, Is.Not.Null); } } The exception: System.NullReferenceException : Object reference not set to an instance of an object. at NHibernate.Linq.NhQueryProvider.PrepareQuery(Expression expression, ref IQuery query, ref NhLinqExpression nhQuery) at NHibernate.Linq.NhQueryProvider.Execute(Expression expression) at System.Linq.Queryable.FirstOrDefault(IQueryable`1 source) The second test: [Test] public void QueryLatestBatch2() { using (var session = SessionManager.OpenSession()) { var batch = session.Query<Batch>() .OrderBy(x => x.Executed) .Take(1) .SingleOrDefault(); Assert.That(batch, Is.Not.Null); } } The exception: System.NullReferenceException : Object reference not set to an instance of an object. at NHibernate.Linq.NhQueryProvider.PrepareQuery(Expression expression, ref IQuery query, ref NhLinqExpression nhQuery) at NHibernate.Linq.NhQueryProvider.Execute(Expression expression) at System.Linq.Queryable.SingleOrDefault(IQueryable`1 source) However, this one is passing (using QueryOver<): [Test] public void QueryOverLatestBatch() { using (var session = SessionManager.OpenSession()) { var batch = session.QueryOver<Batch>() .OrderBy(x => x.Executed).Asc .Take(1) .SingleOrDefault(); Assert.That(batch, Is.Not.Null); Assert.That(batch.Executed, Is.LessThan(DateTime.Now)); } } Using the QueryOver< API is not bad at all, but I'm just kind of baffled that the Query< API isn't working, which is kind of sad, since the First() operation is very concise, and our developers really enjoy LINQ. I really hope there is a solution to this, as it seems strange if these methods are failing such a simple test. EDIT I'm using Oracle 11g, my mappings are done with FluentNHibernate registered through Castle Windsor with the NHibernate Facility. As I wrote, the odd thing is that the query works perfectly with the QueryOver< API, but not through LINQ.

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  • 301 Redirect and query strings

    - by icelizard
    I am looking to create a 301 redirect based purely on a query string see b OLD URL: olddomain.com/?pc=/product/9999 New URL: newurl.php?var=yup My normal way of doing this would be redirect 301 pc=/product/9999 newurl.php?var=yup But this time I am trying to match a URL that that only contains the domain and a query string... What is the best way of doing this? Thanks

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  • MySQL: how to enable Slow Query Log?

    - by Continuation
    Can you give me an example on how to enable MySQL's slow query log? According to the doc: As of MySQL 5.1.29, use --slow_query_log[={0|1}] to enable or disable the slow query log, and optionally --slow_query_log_file=file_name to specify a log file name. The --log-slow-queries option is deprecated. So how do I use that option? Can I put it in my.cnf? An example would be greatly appreciated. Thank you very much

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  • HP Proliant Servers - WMI query for system health

    - by Mike McClelland
    Hi, I want to query lots of HP servers to determine their overall health. I don't want to use any packages, or even SNMP - I want to query the server health from WMI and understand if a box is Green/Amber/Red - just like the HP Management Home Page. This MUST be possible - but I can't find any documentation... Oh yes, and the servers are running Windows Server 2003/8. Help!! Mike

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  • Slow Query log for just one database

    - by Jason
    can I enable the slow query log specifically for just one database? What I've done currently is to take the entire log into excel and then run a pivot report to work out which database is the slowest. So i've gone and done some changes to that application in the hope of reducing the slow query occurence. rather than running my pivot report again which took a bit of time to cleanse the data i'd rather just output slow queries from the one database possible?

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  • How do I make a LDAP query-based dynamic distribution group in Exchange 2010

    - by blsub6
    I see that there were ways in Exchange 2003 and Exchange 2007 to just put in an LDAP query and it would populate the group for you. Is there any way to do that in Exchange 2010? I know there's dynamic distribution groups but I don't want to create the group based on one of their pre-set queries and I don't want to mess around with "custom attributes". I just want to put an LDAP query in there and make it run it to populate the distribution group.

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  • Replace a SQL Server query with another before execution

    - by Kiranu
    I am trying to work with a legacy application in SQL Server which at some point does the following query SELECT serverproperty('EngineEdition') as sqledition The server replies with 2 (which is the correct edition), but the application closes since the app demands to be run over SQL Server Express which is 4. We don't have access to the code and the developer is long gone. Is there a way to configure SQL Server so that when this query is received it simply returns 4 and not the value of the property? Thanks

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  • Oracle Database 12c is here!

    - by Maria Colgan
    Oracle Database 12c was officially release today and is now available for download. Along with the software release comes a whole new set of collateral that explains in detail all of the new features and functionality you will find in this release. The Optimizer page on Oracle.com has all the juicy details about what you can expect from the Optimizer in Oracle Database12c.  There you will find the following 3 new white papers; What to expect from the Oracle Optimizer in Oracle Database 12c SQL Plan Management with Oracle Database 12c Understanding Optimizer Statistics with Oracle Database 12c Over the coming months we will also present an in-depth series of blog posts on all of the cool new Optimizer features in 12c so stay tuned for that and happy reading! +Maria Colgan

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