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  • Query to find all the nodes that are two steps away from a particular node.

    - by iecut
    Suppose I have two columns in a table that represents a graph, the first column is a FROMNODE and second one is TONODE. What I would like to know is that how will we find all the nodes that are two steps away from a particular node. Lets suppose I have a node numbered '1' and i would like to know all the nodes that are two steps away from it. I have tried(I am assuming the table name as graph) SELECT FROMNODE FROM GRAPH WHERE TONODE=1 (this is to select all the nodes that are connected to node 1, but I couldn't figure out how would I find all the nodes that are two steps away from node 1??)

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  • Calling sp and Performance strategy.

    - by Costa
    Hi I find my self in a situation where I have to choose between either creating a new sp in database and create the middle layer code. so loose some precious development time. also the procedure is likely to contain some joins. Or use two existing sp(s), the problem of this approach is that I am doing two round trips to database. which can be poor performance especially if I have database in another server. Which approach you will go?, and why? thanks

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  • Insert rownumber repeatedly in records in t-sql.

    - by jeff
    Hi, I want to insert a row number in a records like counting rows in a specific number of range. example output: RowNumber ID Name 1 20 a 2 21 b 3 22 c 1 23 d 2 24 e 3 25 f 1 26 g 2 27 h 3 28 i 1 29 j 2 30 k I rather to try using the rownumber() over (partition by order by column name) but my real records are not containing columns that will count into 1-3 rownumber. I already try to loop each of record to insert a row count 1-3 but this loop affects the performance of the query. The query will use for the RDL report, that is why as much as possible the performance of the query must be good. any suggestions are welcome. Thanks

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  • Split function in where clause

    - by abhishek-khandelwal
    hello friends I am using following query in linq In product table following type of data are stored abc-def bcd=fgh abc-xyz var query=from prod in db.Product join cat in db.category on prod.categoryId=cat.categoryID where prod.productName.split('-')[0]=="abc" but in that query it product annoumous problem Please give some suggestion to split in where caluse

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  • Conversion failed: SqlParameter and DateTime

    - by Tim
    I'm changing old,vulnerable sqlcommands with SqlParameters but get a SqlException: System.Data.SqlClient.SqlException {"Conversion failed when converting datetime from character string."} on sqlCommand.ExecuteScalar() Dim sqlString As String = _ "SELECT TOP 1 " & _ "fiSL " & _ "FROM " & _ "tabData AS D " & _ "WHERE " & _ "D.SSN_Number = '@SSN_Number' " & _ "AND D.fiProductType = 1 " & _ "AND D.Repair_Completion_Date > '@Repair_Completion_Date' " & _ "ORDER BY " & _ "D.Repair_Completion_Date ASC" Dim obj As Object Dim sqlCommand As SqlCommand Try sqlCommand = New SqlCommand(sqlString, Common.MyDB.SqlConn_RM2) sqlCommand.CommandTimeout = 120 sqlCommand.Parameters.AddWithValue("@SSN_Number", myClaim.SSNNumber) sqlCommand.Parameters.AddWithValue("@Repair_Completion_Date", myClaim.RepairCompletionDate) If Common.MyDB.SqlConn_RM2.State <> System.Data.ConnectionState.Open Then Common.MyDB.SqlConn_RM2.Open() obj = sqlCommand.ExecuteScalar() Catch ex As Exception Dim debug As String = ex.ToString Finally Common.MyDB.SqlConn_RM2.Close() End Try myClaim.RepairCompletionDate is a SQLDateTime. Do i have to remove the quotes in the sqlString to compare Date columns? But then i dont get a exception but incorrect results.

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  • MySQL query advice

    - by vasion
    I am lost in MySQL documentation. I have a table with votes - it has these columns id song_id user_id created I cannot find the query which will process the information and output the 10 most voted songs in a given time period. What is it?

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  • When is referential integrity not appropriate?

    - by Curtis Inderwiesche
    I understand the need to have referential integrity for limiting specific values on entry or possibly preventing them from removal upon a request of deletion. However, I am unclear as to a valid use case which would exclude this mechanism from always being used. I guess this would fall into several sub-questions: When is referential integrity not appropriate? Is it appropriate to have fields containing multiple and/or possibly incomplete subsets of a foreign key's list? Typically, should this be a schema structure design decision or an interface design decision? (Or possibly neither or both) Thoughts?

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  • To log in stored procedures?

    - by hgulyan
    If you have a long running SP, do you log somehow it's actions or just wait for this message? "Command(s) completed successfully." I assume, that there can be plenty solutions on this subject, but is there any best practice - a simple solution that is frequently used?

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  • Where Not In OR Except simulation of SQL in LINQ to Objects

    - by Thinking
    Suppose I have two lists that holds the list of source file names and destination file names respectively. The Sourcefilenamelist has files as 1.txt, 2.txt,3.txt, 4.txt while the Destinaitonlist has 1.txt,2.txt. I ned to write a linq query to find out which files are in SourceList that are absent in DestinationFile list. e.g. here the out put will be 3.txt and 4.txt. I have done this by a foreach statement. but now I want to do the same by using LINQ(C#). Edit: My Code is List<FileList> sourceFileNames = new List<FileList>(); sourceFileNames.Add(new FileList { fileNames = "1.txt" }); sourceFileNames.Add(new FileList { fileNames = "2.txt" }); sourceFileNames.Add(new FileList { fileNames = "3.txt" }); sourceFileNames.Add(new FileList { fileNames = "4.txt" }); List<FileList> destinationFileNames = new List<FileList>(); destinationFileNames.Add(new FileList { fileNames = "1.txt" }); destinationFileNames.Add(new FileList { fileNames = "2.txt" }); IEnumerable<FileList> except = sourceFileNames.Except(destinationFileNames); And Filelist is a simple class with only one property fileNames of type string.

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  • MySQL foreign key creation with alter table command

    - by user313338
    I created some tables using MySQL Workbench, and then did forward ‘forward engineer’ to create scripts to create these tables. BUT, the scripts lead me to a number of problems. One of which involves the foreign keys. So I tried creating separate foreign key additions using alter table and I am still getting problems. The code is below (the set statements, drop/create statements I left in … though I don’t think they should matter for this): SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0; SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0; SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL'; DROP SCHEMA IF EXISTS `mydb` ; CREATE SCHEMA IF NOT EXISTS `mydb` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci ; -- ----------------------------------------------------- -- Table `mydb`.`User` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User` ; CREATE TABLE IF NOT EXISTS `mydb`.`User` ( `UserName` VARCHAR(35) NOT NULL , `Num_Accts` INT NOT NULL , `Password` VARCHAR(45) NULL , `Email` VARCHAR(45) NULL , `User_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_ID`) ) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `mydb`.`User_Space` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User_Space` ; CREATE TABLE IF NOT EXISTS `mydb`.`User_Space` ( `User_UserName` VARCHAR(35) NOT NULL , `User_Space_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_Space_ID`), FOREIGN KEY (`User_UserName`) REFERENCES `mydb`.`User` (`UserName`) ON UPDATE CASCADE ON DELETE CASCADE) ENGINE = InnoDB; SET SQL_MODE=@OLD_SQL_MODE; SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS; SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS; The error this produces is: Error Code: 1005 Can't create table 'mydb.user_space' (errno: 150) Anybody know what the heck I’m doing wrong?? And anybody else have problems with the script generation done by mysql workbench? It’s a nice tool, but annoying that it pumps out scripts that don’t work for me. [As an fyi here’s the script it auto-generates: SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0; SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0; SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL'; DROP SCHEMA IF EXISTS `mydb` ; CREATE SCHEMA IF NOT EXISTS `mydb` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci ; -- ----------------------------------------------------- -- Table `mydb`.`User` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User` ; CREATE TABLE IF NOT EXISTS `mydb`.`User` ( `UserName` VARCHAR(35) NOT NULL , `Num_Accts` INT NOT NULL , `Password` VARCHAR(45) NULL , `Email` VARCHAR(45) NULL , `User_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_ID`) ) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `mydb`.`User_Space` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User_Space` ; CREATE TABLE IF NOT EXISTS `mydb`.`User_Space` ( `User_Space_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_Space_ID`) , INDEX `User_ID` () , CONSTRAINT `User_ID` FOREIGN KEY () REFERENCES `mydb`.`User` () ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; SET SQL_MODE=@OLD_SQL_MODE; SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS; SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS; ** Thanks!]

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  • MySQL slow query

    - by andrhamm
    SELECT items.item_id, items.category_id, items.title, items.description, items.quality, items.type, items.status, items.price, items.posted, items.modified, zip_code.state_prefix, zip_code.city, books.isbn13, books.isbn10, books.authors, books.publisher FROM ( ( items LEFT JOIN bookitems ON items.item_id = bookitems.item_id ) LEFT JOIN books ON books.isbn13 = bookitems.isbn13 ) LEFT JOIN zip_code ON zip_code.zip_code = items.item_zip WHERE items.rid = $rid` I am running this query to get the list of a user's items and their location. The zip_code table has over 40k records and this might be the issue. It currently takes up to 15 seconds to return a list of about 20 items! What can I do to make this query more efficient?

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  • postgresql: Fast way to update the latest inserted row

    - by Anonymous
    What is the best way to modify the latest added row without using a temporary table. E.g. the table structure is id | text | date My current approach would be an insert with the postgresql specific command "returning id" so that I can update the table afterwards with update myTable set date='2013-11-11' where id = lastRow However I have the feeling that postgresql is not simply using the last row but is iterating through millions of entries until "id = lastRow" is found. How can i directly access the last added row?

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  • Group keywords by site

    - by Skudd
    I am finding a lot of useful help here today, and I really appreciate it. This should be the last one for the day: I have a list of the top 10 keywords per site, sorted by visits, by date. The records need to be sorted as follows (excuse the formatting): 2010-05 2010-04 site1.com keyword1 apples wine keyword1 visits 100 12 keyword2 oranges water keyword2 visits 99 10 site2.com keyword1 blueberry cornbread keyword1 visits 90 100 keyword2 squares biscuits keyword2 visits 80 99 Basically what I need to accomplish involves grouping, but I can't seem to figure it out. Am I heading down the right path, or is there another way to achieve this, or is it just impossible?

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  • How to calculate the sum of a column in an MS Access table for a given date (a single day, month or year)

    - by cMinor
    I have a table in Access in a custom format saved as dd/MM/yyyy hh:mm:ss tt , Also A form in VB.NET 2010, I get a specific day, month and year with no problem but the problem comes when I want to query the sum of a column named value depending on a specific month or day or year.... The table is like: +-----+-----------+-------------------------+ | id | value | date | +-----+-----------+-------------------------+ | id1 | 1499 | 01/01/2012 07:30:11 p.m.| | id2 | 1509 | 11/02/2012 07:30:11 p.m.| | id3 | 1611 | 21/10/2012 07:30:11 p.m.| | id1 | 1115 | 11/10/2012 07:30:11 p.m.| | id1 | 1499 | 17/05/2012 07:30:11 p.m.| | id2 | 1709 | 11/06/2012 07:30:11 p.m.| | id3 | 1911 | 30/07/2012 07:30:11 p.m.| | id1 | 1015 | 01/08/2012 07:30:11 p.m.| | id1 | 1000 | 11/05/2012 07:30:11 p.m.| |+-----+-----------+------------------------+ So I Know the query SELECT SUM(value) FROM mytable WHERE date in='01/05/2012 00:00:00' ... How to tell the query I want the month of May so I would get 1499+1000= 2499 Or how to tell I want the year 2012 so I would get the sum of all the table Which would be the correct syntax...

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  • Why would I do an inner join on a non-distinct field?

    - by froadie
    I just came across a query that does an inner join on a non-distinct field. I've never seen this before and I'm a little confused about this usage. Something like: SELECT distinct all, my, stuff FROM myTable INNER JOIN myOtherTable ON myTable.nonDistinctField = myOtherTable.nonDistinctField (WHERE some filters here...) I'm not quite sure what my question is or how to phrase it, or why exactly this confuses me, but I was wondering if anyone could explain why someone would need to do an inner join on a non-distinct field and then select only distinct values...? Is there ever a legitimate use of an inner join on a non-distinct field? What would be the purpose? And if there's is a legitimate reason for such a query, can you give examples of where it would be used?

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  • Replacing characters with specified one

    - by mahesh
    Hello All, I have a string as follows - MFMFMF now i want to change this string to FMFMFM how to do this , help needed pls i had tried select replace(replace('mfmfmf','M','F'),'F','M') this gives me result - MMMMMM which i donot what i want the output to be FMFMFM Need your help D.Mahesh

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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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  • Concatenating rows from different tables into one field

    - by Markus
    Hi! In a project using a MSSQL 2005 Database we are required to log all data manipulating actions in a logging table. One field in that table is supposed to contain the row before it was changed. We have a lot of tables so I was trying to write a stored procedure that would gather up all the fields in one row of a table that was given to it, concatenate them somehow and then write a new log entry with that information. I already tried using FOR XML PATH and it worked, but the client doesn't like the XML notation, they want a csv field. Here's what I had with FOR XML PATH: DECLARE @foo varchar(max); SET @foo = (SELECT * FROM table WHERE id = 5775 FOR XML PATH('')); The values for "table", "id" and the actual id (here: 5775) would later be passed in via the call to the stored procedure. Is there any way to do this without getting XML notation and without knowing in advance which fields are going to be returned by the SELECT statement?

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  • archiving strategies and limitations of data in a table

    - by Samuel
    Environment: Jboss, Mysql, JPA, Hibernate Our web application will be catering to a large amount of users (~ 1,000,000) and there are a lots of child table where user specific data are stored (e.g. personal, health, forum contributions ...). What would be the best practice to archive user & user specific information. [a] Would it be wise to move the archived user & user specific information to their respective tables within the same database (e.g. user_archive, user_forum_comments_archive ...) OR [b] Would you just mark the database entries with a flag in the original table(s) and just query only non archived entries. We have a unique constraint on User.loginid, how do you handle this requirement if the users are archived via 1-[a] (i.e if a user with loginid 'samuel' gets moved into the archive table and if a new user gets added with the same name in the original table, how would you prevent this. What would be the best strategy to address the unique key constraints. We have a requirement to selectively archive records and bring it back if necessary, will you rely on database tools are would you handle this via your persistence APIs exposed by the JPA entity model.

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  • How do views reduce code duplication?

    - by Debuger
    Hi! I read something like this about db views: Views are incredibly powerful and useful for one reason that stands out above all the other very good reasons. They reduce code duplication. That is, in most cases, the bottom line. If a query will be used in three or more places, then a view will drastically simplify your changes if the schema or query parameters change. I once had to edit 22 stored procedures to change some query logic. If the original architecture had utilized views, then I would have had only three changes. Can anyone explain to me how it works, and maybe give me some examples? Best regards!

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  • How to switch from MSSQL to MySQL for using with Excel pivot

    - by Sim
    Hi all, I have a table that contains sales transaction (~20 mil rows). Previously I used MSSQL and export it to an Excel pivot. Data refresh took 10-15 minutes but still do-able. However, after I migrated to MySQL (using XamppLite & ODBC), it took forever to refresh the data in the Excel pivot. Maybe I didn't optimize the MySQL good enough ? Anyone can share some thoughts 'bout this ? Thanks

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  • Do a query only if there are no results on previous query

    - by yes123
    Hi guys: I do this query(1): (1)SELECT * FROM t1 WHERE title LIKE 'key%' LIMIT 1 I need to do a second(2) query only if this previous query has no results (2)SELECT * FROM t1 WHERE title LIKE '%key%' LIMIT 1 basically i need only 1 row who got the most close title to my key. Atm i am using an UNION query with a custom field to order it and a LIMIT 1. Problem is I don't want to do the others query if already the first made the result. Thanks

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  • How to write this Link2Sql select query

    - by RememberME
    I have 3 tables: subcontracts, companies and contacts. Each table has a active_status flags which shows that the item is still active (hasn't been deleted). Each contact has a company_id field which stores the id of the contact's company. Each subcontract has a company_id field which stores the subcontract's company. Each company has a company_id field which holds its guid and a primary_company field, b/c the company could be a subsidiary. If it's a subsidiary, the primary_company field holds the id of the primary company. I have a subcontract form. On the form, I have a drop-down of contacts which are stored in a contact table. Currently the drop-down lists all contacts. I would like to have the drop-down only list contacts which belong to the subcontract's company or any of that company's subsidiaries. I have the following query which I use elsewhere in the program to pass a company_id and get its subsidiaries. public IQueryable<company> GetSubsidiaryCompanies(Guid id) { return from c in db.companies where c.primary_company == id && c.active_status == true select c; } This is my current contact selection public IQueryable<contact> GetContacts() { return from c in db.contacts where c.active_status == true orderby c.contact_name select c; } What I need to do is pass it the subcontract.company_id and then only return the contacts where contact.company_id == subcontract.company_id or contact.company_id == one of the subsidiary ids.

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  • What resources will help me understand the fundamentals of Relational Database Systems.

    - by Rachel
    This are few of the fundamental database questions which has always given me trouble. I have tried using google and wiki but I somehow I miss out on understanding the functionality rather than terminology. If possible would really appreciate if someone can share more insights on this questions using some visual representative examples. What is a key? A candidate key? A primary key? An alternate key? A foreign key? What is an index and how does it help your database? What are the data types available and when to use which ones?

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