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  • What will happen if I change the type of a column from int to year?

    - by MachinationX
    I have a table in MySQL 4.0 which currently has a year field as a smallint(6) type. What will happen if I convert it directly to a Year type with a query like the following: ALTER TABLE t MODIFY y YEAR(4) NOT NULL DEFAULT CURRENT_TIMESTAMP; When the current members of column y have values like 2010? I assume that because the year type is technically values from 1-255, values above that will be truncated or broken. So if MySQL isn't smart enough to realize that 2010(int) = 110(year), what would be the simplest query or queries to convert the values? Thanks for your help!

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  • Three-way full outer join in SQLite

    - by Vince
    I have three tables with a common key field, and I need to join them on this key. Given SQLite doesn't have full outer or right joins, I've used the full outer join without right join technique on Wikipedia with much success. But I'm curious, how would one use this technique to join three tables by a common key? What are the efficiency impacts of this (the current query takes about ten minutes)? Thanks!

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  • Beginner having difficulty with SQL query

    - by Vulcanizer
    Hi, I've been studying SQL for 2 weeks now and I'm preparing for an SQL test. Anyway I'm trying to do this question: For the table: 1 create table data { 2 id int, 3 n1 int not null, 4 n2 int not null, 5 n3 int not null, 6 n4 int not null, 7 primary key (id) 8 } I need to return the relation with tuples (n1, n2, n3) where all the corresponding values for n4 are 0. The problem asks me to solve it WITHOUT using subqueries(nested selects/views) It also gives me an example table and the expected output from my query: 01 insert into data (id, n1, n2, n3, n4) 02 values (1, 2,4,7,0), 03 (2, 2,4,7,0), 04 (3, 3,6,9,8), 05 (4, 1,1,2,1), 06 (5, 1,1,2,0), 07 (6, 1,1,2,0), 08 (7, 5,3,8,0), 09 (8, 5,3,8,0), 10 (9, 5,3,8,0); expects (2,4,7) (5,3,8) and not (1,1,2) since that has a 1 in n4 in one of the cases. The best I could come up with was: 1 SELECT DISTINCT n1, n2, n3 2 FROM data a, data b 3 WHERE a.ID <> b.ID 4 AND a.n1 = b.n1 5 AND a.n2 = b.n2 6 AND a.n3 = b.n3 7 AND a.n4 = b.n4 8 AND a.n4 = 0 but I found out that also prints (1,1,2) since in the example (1,1,2,0) happens twice from IDs 5 and 6. Any suggestions would be really appreciated.

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  • what does "out of range" mean?

    - by user329820
    Hi I have checked these statements with mysql and no error will happen and also the out put will be 0 rows BUT my friend checked it and he found an error for SELECT becaouse it is out of range !! IS he correct? thanks CREATE TABLE T1(A INTEGER NULL); SELECT * FROM T1;

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  • How to get only one record for each duplicate rows of the id in oracle?

    - by Psychocryo
    suppose i have this table: group_id | image | image_id | ----------------------------- 23 blob 1 23 blob 2 23 blob 3 21 blob 4 21 blob 5 25 blob 6 25 blob 7 how to get results of only 1 of each group id? in this case,there may be multiple images for one group id, i just want one result of each group_id i tried distinct but i will only get group_id. max for image also would not work.

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  • How to translate this 2 queries from Mysql to Postgresql? :

    - by xRobot
    How can I translate this 2 queries in postgresql ? : CREATE TABLE `example` ( `id` int(10) unsigned NOT NULL auto_increment, `from` varchar(255) NOT NULL default '0', `message` text NOT NULL, `lastactivity` timestamp NULL default '0000-00-00 00:00:00', `read` int(10) unsigned NOT NULL, PRIMARY KEY (`id`), KEY `from` (`from`) ) DEFAULT CHARSET=utf8; Query: SELECT * FROM table_1 LEFT OUTER JOIN table_2 ON ( table_1.id = table_2.id ) WHERE (table_1.lastactivity > NOW()-100);

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  • Set to null a parent record so that children are removed: howto?

    - by EugeneP
    How to delete a child row (on delete cascade ?) when setting a null value on a parent? Here's the db design. table A [id, b_id_1, b_id_2] table B [id, other fields...] b_id_1 and b_id_2 can be NULL if any of them is null, it means NO B records for corresponding FK (there are 2 of them) so (b_id_1,b_id_2) can be (null,null), (100, null), (null, 100_or_any_other_number) etc How in one SQL query both set b_id_1 or b_id_2 to null and delete all rows from B that have this id? What FK design should be applied to the 2 tables? what foreign keys should be added? A - B (FK_1: A.b_id_1 references B.id, FK_2: A.b_id_2 references B.id) and also B-A (FK_3: B.id references A.b_id_1, FK_4: B.id references A.b_id_2) ? But again, setting an A's b_id_1 or A's b_id_2 to null - will it remove any of B's records? I don't think so. So how to do that?

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  • Aggregation over a few models - Django

    - by RadiantHex
    Hi folks, I'm trying to compute the average of a field over various subsets of a queryset. Player.objects.order_by('-score').filter(sex='male').aggregate(Avg('level')) This works perfectly! But... if I try to compute it for the top 50 players it does not work. Player.objects.order_by('-score').filter(sex='male')[:50].aggregate(Avg('level')) This last one returns the exact same result as the query above it, which is wrong. What am I doing wrong? Help would be very much appreciated!

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  • SQL Server 2005: Rename DB Server Instance Name?

    - by Code Sherpa
    Hi, Can somebody tell me how to rename the DB server instance name and a DB name in SQL Server 2005? Right Now I Have SERVER/OLDNAME -- oldnameDB I want to change the server instance and also change the db name. I have tried: EXEC sp_renamedb 'oldName', 'newName' and that has changed the dbname as it appers in the tree directory. But, when I do "select @@servername" it is the old name. Also, the MDF and LDF files are still the old name. How do change instance and db names as a clean sweep across the server? Thanks.

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  • Good basic tutorial for installing and using SqlServer

    - by ripper234
    I know mysql, and I'd like to learn sqlserver. I'm currently stuck on the basics of basics: How to install and configure sql server How to connect to it I installed Sql Server through Web Platform Installer, and have Visual Studio 2008 installed. Still, I can't understand how to connect to my server: I see that the SQL service itself (SQLEXPRESS) is running in both in services.msc and Sql Server Configuration Manager I try to connect to it via the Management Studio, but I don't understand what to do. Where do I begin?

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  • help with delete where not in query

    - by kralco626
    I have a lookup table (##lookup). I know it's bad design because I'm duplicating data, but it speeds up my queries tremendously. I have a query that populates this table insert into ##lookup select distinct col1,col2,... from table1...join...etc... I would like to simulate this behavior: delete from ##lookup insert into ##lookup select distinct col1,col2,... from table1...join...etc... This would clearly update the table correctly. But this is a lot of inserting and deleting. It messes with my indexes and locks up the table for selecting from. This table could also be updated by something like: delete from ##lookup where not in (select distinct col1,col2,... from table1...join...etc...) insert into ##lookup (select distinct col1,col2,... from table1...join...etc...) except if it is already in the table The second way may take longer, but I can say "with no lock" and I will be able to select from the table. Any ideas on how to write the query the second way?

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  • Solr autocommit and autooptimize?

    - by Camran
    I will be uploading my website to a VPS soon. It is a classifieds website which uses Solr integrated with MySql. Solr is updated whenever a new classified is put or deleted. I need a way to make the commit() and optimize() be automated, for example once every 3 hours or so. How can I do this? (Details Please) When is it ideal to optimize? Thanks

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  • MySQL Limiting a query to one consistent value

    - by Lucas Matos
    My current query returns a table like: +------------+ value1 | .... value1 | .... value2 | .... value3 | .... +------------+ I want: +------------+ value1 | .... value1 | .... +------------+ I want to only receive all rows with the first value. Normally I would do a WHERE clause if I knew that value, and I cannot use a LIMIT because each value has a different number of rows. Right now My query looks like "SELECT u.*, n.something, w.* FROM ... AS u, ... AS n, ... AS w WHERE u.id = n.id AND w.val = n.val AND u.desc LIKE '%GET REQUEST VARIABLE%';" This works great, except I get way too many rows and using PHP to do this ruins code portability and is superfluous. Thanks for reading

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  • Static selection and Ruby on Rails objects

    - by Dave
    Hi all- I have a simple problem, but am having trouble wrapping my head around it. I have an video object that should have one or more "genres". This list of genres should be prepopulated and then the user should just select one or more using autocomplete or some such. Here is the question: Is it worth creating a table with genres for the static selection? Or should it just be included in the presentation layer? If there is a static table, how do we name it correctly. I envision something like this class Video < ActiveRecord::Base has_many :genres ... end class Genre < ... belongs_to :video ... end But then we get a table called genre, that basically maps all the selected genres to their parent videos. There would need to be some static table to reference the static genres. Is this the best way to do it? Sorry if this was rambl-y a little stream of conciousness. Thanks!

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  • How can an improvement to the query cache be tracked?

    - by Bill Paetzke
    I am parameterizing my web app's ad hoc sql. As a result, I expect the query plan cache to reduce in size and have a higher hit ratio. Perhaps even other important metrics will be improved. Could I use perfmon to track this? If so, what counters should I use? If not perfmon, how could I report on the impact of this change?

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  • db optimization - have a total field or query table?

    - by Dorian Fife
    I have an app where users get points for actions they perform - either 1 point for an easy action or 2 for a difficult one. I wish to display to the user the total number of points he got in my app and the points obtained this week (since Monday at midnight). I have a table that records all actions, along with their time and number of points. I have two alternatives and I'm not sure which is better: Every time the user sees the report perform a query and sum the points the user got Add two fields to each user that records the number of points obtained so far (total and weekly). The weekly points value will be set to 0 every Monday at midnight. The first option is easier, but I'm afraid that as I'll get many users and actions queries will take a long time. The second option bares the risk of inconsistency between the table of actions and the summary values. I'm very interested in what you think is the best alternative here. Thanks, Dorian

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  • mysql query to get unique value from one column

    - by vesselyp
    i have a table named locations of which i want to select and get values in such a way that it should select only distinct values from a column but select all other values . table name: locations column names 1: country values : America, India, India, India column names 2: state/Province : Newyork, Punjab, Karnataka, kerala when i select i should get India only once and all the three states listed under India . is ther any way..??? sombody please help

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  • In a SQL XDL File, how do I read the waitresource attribute on process nodes which are deadlocking?

    - by skimania
    On SQL Server 2005, I'm getting a deadlock when updating two different keys in the same table. note from below that these two waitresources have the same beginning part, but different ending parts. waitresource="KEY: 6:72057594090487808 (d900ed5a6cc6)" and waitresource="KEY: 6:72057594090487808 (d900fb5261bb)" These two keys are locking, and I need to figure out why. The question: If the values in parenthesis are different, why are the first half of the key's the same? <deadlock-list> <deadlock victim="processffffffff8f5863e8"> <process-list> <process id="processaf02f8" taskpriority="0" logused="0" waitresource="KEY: 6:72057594090487808 (d900fb5261bb)" waittime="2281" ownerId="1370264705" transactionname="user_transaction" lasttranstarted="2010-06-17T00:35:25.483" XDES="0x69453a70" lockMode="U" schedulerid="3" kpid="7624" status="suspended" spid="339" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-17T00:35:25.483" lastbatchcompleted="2010-06-17T00:35:25.483" clientapp=".Net SqlClient Data Provider" hostname="RISKBBG_VM" hostpid="5848" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1370264705" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056"> <executionStack> <frame procname="MKP_RISKDB.dbo.MarketDataCurrentRtUpload" line="14" stmtstart="840" stmtend="1220" sqlhandle="0x03000600005f9d24c8878f00849d00000100000000000000"> UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid; -- Insert new MDID </frame> <frame procname="adhoc" line="1" sqlhandle="0x010006004a58132228bf8d73000000000000000000000000"> MarketDataCurrentBlbgRtUpload </frame> </executionStack> <inputbuf> MarketDataCurrentBlbgRtUpload </inputbuf> </process> <process id="processffffffff8f5863e8" taskpriority="0" logused="0" waitresource="KEY: 6:72057594090487808 (d900ed5a6cc6)" waittime="2281" ownerId="1370264646" transactionname="user_transaction" lasttranstarted="2010-06-17T00:35:25.450" XDES="0x1cb72be8" lockMode="U" schedulerid="5" kpid="1880" status="suspended" spid="287" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-17T00:35:25.450" lastbatchcompleted="2010-06-17T00:35:25.450" clientapp=".Net SqlClient Data Provider" hostname="RISKAPPS_VM" hostpid="1424" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1370264646" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056"> <executionStack> <frame procname="MKP_RISKDB.dbo.MarketDataCurrent_BulkUpload" line="28" stmtstart="1062" stmtend="1720" sqlhandle="0x03000600a28e5e4ef4fd8e00849d00000100000000000000"> UPDATE c WITH (ROWLOCK) SET LastUpdate = getdate(), Value = t.Value, Source = @source FROM MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid WHERE c.lastUpdate &lt; @updateTime and c.mdid not in (select mdid from MarketData where BloombergTicker is not null and PriceSource like &apos;Live.%&apos;) and c.value &lt;&gt; t.value </frame> <frame procname="adhoc" line="1" stmtstart="88" sqlhandle="0x01000600c1653d0598706ca7000000000000000000000000"> exec MarketDataCurrent_BulkUpload @clearBefore, @source </frame> <frame procname="unknown" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000"> unknown </frame> </executionStack> <inputbuf> (@clearBefore datetime,@source nvarchar(10))exec MarketDataCurrent_BulkUpload @clearBefore, @source </inputbuf> </process> </process-list> <resource-list> <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lock64ac7940" mode="U" associatedObjectId="72057594090487808"> <owner-list> <owner id="processffffffff8f5863e8" mode="U"/> </owner-list> <waiter-list> <waiter id="processaf02f8" mode="U" requestType="wait"/> </waiter-list> </keylock> <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lockffffffffb8d2dd40" mode="U" associatedObjectId="72057594090487808"> <owner-list> <owner id="processaf02f8" mode="U"/> </owner-list> <waiter-list> <waiter id="processffffffff8f5863e8" mode="U" requestType="wait"/> </waiter-list> </keylock> </resource-list> </deadlock> </deadlock-list>

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