Search Results

Search found 40744 results on 1630 pages for 'sql interview questions a'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 714/1630 | < Previous Page | 710 711 712 713 714 715 716 717 718 719 720 721  | Next Page >

  • Conditional sorting in MySQL?

    - by serg555
    I have "tasks" table with 3 fields: date priority (0,1,2) done (0,1) What I am trying to achieve is with the whole table sorted by done flag, tasks that are not done should be sorted by priority, while tasks that are done should be sorted by date: Select * from tasks order by done asc If done=0 additionally order by priority desc If done=1 additionally order by date desc Is it possible to do this in MySQL without unions? Thanks.

    Read the article

  • user_objects oracle

    - by mysticfalls
    I would just like to ask what is the difference between user_constraints and user_objects. I have this two database. I run a script on both DB that resulted a unique constraint error. To solve the problem I delete the constraint on user_constraint table for both DB. After that DB1 run without error.. DB2 however failed, I checked the user_constraint for both db and the constraints was deleted. I was asked to check the user_objects.. and found that DB2 has that same constraint_name as the object_name in user_objects table.. Any info regarding their relationship, use, similarites, etc will be appreciated ... Thanks..

    Read the article

  • Voting Script, Possiblity of Simplifying Database Queries

    - by Sev
    I have a voting script which stores the post_id and the user_id in a table, to determine whether a particular user has already voted on a post and disallow them in the future. To do that, I am doing the following 3 queries. SELECT user_id, post_id from votes_table where postid=? AND user_id=? If that returns no rows, then: UPDATE post_table set votecount = votecount-1 where post_id = ? Then SELECT votecount from post where post_id=? To display the new votecount on the web page Any better way to do this? 3 queries are seriously slowing down the user's voting experience

    Read the article

  • SqlCeCommand ExecuteNonQuery performance issue

    - by Michael
    I've been asked to resolve an issue with a .Net/SqlServerCe application. Specifically, after repeated inserts against the db, performance becomes increasingly degraded. In one instance at ~200 rows, in another at ~1000 rows. In the latter case the code being used looks like this: Dim cm1 As System.Data.SqlServerCe.SqlCeCommand = cn1.CreateCommand cm1.CommandText = "INSERT INTO Table1 Values(?,?,?,?,?,?,?,?,?,?,?,?,?)" For j = 0 To ds.Tables(0).Rows.Count - 1 'this is 3110 For i = 0 To 12 cm1.Parameters(tbl(i, 0)).Value = Vals(j,i) 'values taken from a different db Next cm1.ExecuteNonQuery() Next The specifics aren't super important (like what 'tbl' is, etc) but rather whether or not this code should be expected to handle this number of inserts, or if the crawl I'm witnessing is to be expected.

    Read the article

  • Query for multiple joins

    - by Shailaja
    i have 3 tables named dataset,dataelem and transformdataelem with column names as below: main.Dataset ------------ datasetID (PK) applicationID main.Dataelem ------------- dataelemID(PK) datasetID(FK) dataelemname biztermID main.Transformdataelem ---------------------- OutputdataelemID InputdataelemID My requirement is: All tables are referenced. Extract all the dataelemId rows from dataelem table where applicationID of dataset table is equal to 1044 and biztermid shud be null. Then whatever resultant dataelemIDs from the above query should be matched with outputdataelemID of Transformdataelem table and we shud get the respective input dataelemId's. Again with these matched inputdataelemID's we shud get the dataelemname's from datelem table.

    Read the article

  • AJAX in ASP.NET - How do I check a checkbox and have the action reflected in the database?

    - by hamlin11
    This is about as beginner as it gets regarding AJAX, but here it goes. I want to have one checkbox somewhere on an ASP.NET web form (ASPX). When the user clicks the checkbox, I want one of those spinning indicators to show. While that spinning indicator is showing, I want an update operation to occur in the database to reflect that the user has intended for that checkbox to be checked. update MyTable set CheckboxChecked = 1 Then, as soon as the update operation has occurred, I want that to be reflected in the checkbox by removing the spinning indicator and replacing it with the standard checked checkbox. I'm guessing this is done with an UpdatePanel and possibly an update statement followed by a looped call to a select statement... but I have never used AJAX before and have no idea how to go about it. Thanks!

    Read the article

  • How to renumber primary index.

    - by Kamil Mroczek
    I have got a simple MySQL table and primary index (id) is not numbered one by one (1, 31, 35, 100 etc.). I want them to be numbered like (1, 2, 3, 4). Please tell me how to do it. I would also like to point that I am aware of possible consequences of the operation, but I just want to tidy up the table.

    Read the article

  • Can I lock rows in a cursor if the cursor only returns a single count(*) row?

    - by RenderIn
    I would like to restrict users from inserting more than 3 records with color = 'Red' in my FOO table. My intentions are to A) retrieve the current count so that I can determine whether another record is allowed and B) prevent any other processes from inserting any Red records while this one is in process, hence the for update of. I'd like to do something like: cursor cur_cnt is select count(*) cnt from foo where foo.color = 'Red' for update of foo.id; Will this satisfy both my requirements or will it not lock only the rows in the count(*) who had foo.color = 'Red'?

    Read the article

  • Is SQLlite strong enough to use as wordpress database ?

    - by justjoe
    i'm just curious. so i ask this particular question about SQLite. I haven't use this type of database extensively. but care to explain what is the basic different between SQLite and Mysql ? The reason behind all of this is i just want to know whether it possible to use it to store wordpress data and act as a database ?

    Read the article

  • How do I do a table join on two fields in my second table?

    - by Cannonade
    I have two tables: Messages - Amongst other things, has a to_id and a from_id field. People - Has a corresponding person_id I am trying to figure out how to do the following in a single linq query: Give me all messages that have been sent to and from person x (idself). I had a couple of cracks at this. Not quite right MsgPeople = (from p in db.people join m in db.messages on p.person_id equals m.from_id where (m.from_id == idself || m.to_id == idself) orderby p.name descending select p).Distinct(); This almost works, except I think it misses one case: "people who have never received a message, just sent one to me" How this works in my head So what I really need is something like: join m in db.messages on (p.people_id equals m.from_id or p.people_id equals m.to_id) Gets me a subset of the people I am after It seems you can't do that. I have tried a few other options, like doing two joins: MsgPeople = (from p in db.people join m in AllMessages on p.person_id equals m.from_id join m2 in AllMessages on p.person_id equals m2.to_id where (m2.from_id == idself || m.to_id == idself) orderby p.name descending select p).Distinct(); but this gives me a subset of the results I need, I guess something to do with the order the joins are resolved. My understanding of LINQ (and perhaps even database theory) is embarrassingly superficial and I look forward to having some light shed on my problem.

    Read the article

  • Broken count(*) after adding LEFT JOIN

    - by Iain Urquhart
    Since adding the LEFT JOIN to the query below, the count(*) has been returning some strange values, it seems to have added the total rows returned in the query to the 'level': SELECT `n`.*, exp_channel_titles.*, round((`n`.`rgt` - `n`.`lft` - 1) / 2, 0) AS childs, count(*) - 1 + (`n`.`lft` > 1) + 1 AS level, ((min(`p`.`rgt`) - `n`.`rgt` - (`n`.`lft` > 1)) / 2) > 0 AS lower, (((`n`.`lft` - max(`p`.`lft`) > 1))) AS upper FROM `exp_node_tree_6` `n` LEFT JOIN `exp_channel_titles` ON (`n`.`entry_id`=`exp_channel_titles`.`entry_id`), `exp_node_tree_6` `p`, `exp_node_tree_6` WHERE `n`.`lft` BETWEEN `p`.`lft` AND `p`.`rgt` AND ( `p`.`node_id` != `n`.`node_id` OR `n`.`lft` = 1 ) GROUP BY `n`.`node_id` ORDER BY `n`.`lft` I'm totally stumped... Thank you!

    Read the article

  • Some help needed with a SQL query

    - by Psyche
    Hello, I need some help with a MySQL query. I have two tables, one with offers and one with statuses. An offer can has one or more statuses. What I would like to do is get all the offers and their latest status. For each status there's a table field named 'added' which can be used for sorting. I know this can be easily done with two queries, but I need to make it with only one because I also have to apply some filters later in the project. Here's my setup: CREATE TABLE `test`.`offers` ( `id` INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY , `client` TEXT NOT NULL , `products` TEXT NOT NULL , `contact` TEXT NOT NULL ) ENGINE = MYISAM ; CREATE TABLE `statuses` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `offer_id` int(11) NOT NULL, `options` text NOT NULL, `deadline` date NOT NULL, `added` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1

    Read the article

  • Comma separated values in a database field

    - by John Doe
    I have a products table. Each row in that table corresponds to a single product and it's identified by a unique Id. Now each product can have multiple "codes" associated with that product. For example: Id | Code ---------------------- 0001 | IN,ON,ME,OH 0002 | ON,VI,AC,ZO 0003 | QA,PS,OO,ME What I'm trying to do is create a stored procedure so that I can pass in a codes like "ON,ME" and have it return every product that contains the "ON" or "ME" code. Since the codes are comma separated, I don't know how I can split those and search them. Is this possible using only TSQL? Edit: It's a mission critical table. I don't have the authority to change it.

    Read the article

  • How do I put data from multiple records into different columns?

    - by Bryan
    My two tables are titled analyzed and analyzedCopy3. I'm trying to put information from analyzedCopy3 into multiple columns in analyzed. Sample data from analyzedCopy3: readings_miu_id OriginalCol ColRSSIz 110001366 Frederick Road -108 110001366 Steel Street 110001366 Fifth Ave. 110001508 Steel Street -104 What I want to do is put the top 3 OriginalCol, ColRSSIz combinations into columns that I have in the table analyzed. In analyzed there is only one record for each unique readings_miu_id. Any ideas? Thanks in advance. Additional Info: By "top 3 OriginalCol, ColRSSIz combinations" I mean the first 3 combinations with the highest value in the ColRSSIz column. For any readings_miu_id there could be anywhere from 1 row of information to 6 rows of information. So at most I'm only wanting the top 3. If there is less than 3 rows for the readings_miu_id then the other columns need to be blank. Query that generates the table "analyzed": strSql4 = " SELECT readings_miu_id, Count(readings_miu_id) as NumberOfReads, First(PercentSuccessz) as PercentSuccess, First(Readingz)as Reading, First(MIUwindowz) as MIUwindow, First(SNz) as SN, First(Noisez) as Noise, First(RSSIz) as RSSI, First(ColRSSIz) as ColRSSI, First(MIURSSIz) as MIURSSI, First(Col1z) as Col1, First(Col1RSSIz) as Col1RSSI, First(Col2z) as Col2, First(Col2RSSIz) as Col2RSSI, First(Col3z) as Col3, First(Col3RSSIz) as Col3RSSI, First(Firmwarez) as Firmware, First(CFGDatez) as CFGDate, First(FreqCorrz) as FreqCorr, First(Activez) as Active, First(MeterTypez) as MeterType, First(OriginColz) as OriginCol, First(ColIDz) as ColID, First(Ownagez) as Ownage, First(SiteIDz) as SiteID, First(PremIDz) as PremID, First(prem_group1z) as prem_group1, First(prem_group2z) as prem_group2, First(ReadIDz) as ReadID, First(prem_addr1z) as prem_addr1 " & _ "INTO analyzed " & _ "FROM analyzedCopy2 " & _ "GROUP BY readings_miu_id, PremIDz; " DoCmd.SetWarnings False DoCmd.RunSQL strSql4 DoCmd.SetWarnings True

    Read the article

  • iPhone SDK: Data Synchronization

    - by buzzappsoftware
    I am looking for an overview of data synchronization techniques available on the iPhone platform. We need the ability to be able to sync a subset of content from a server to a local database residing on the iPhone. On other projects I have worked on, the data synchronization was handled by the database. Is that available in SQLite? If not, any suggestions on techniques? Rolling our own would not be my first choice. Thanks in advance.

    Read the article

  • Any way to make this PostgreSQL count query any faster?

    - by Ben Dauphinee
    I'm running a case-insensitive search on a table with 7.2 million rows, and I was wondering if there was any way to make this query any faster? Currently, it takes approx 11.6 seconds to execute, with just one search parameter, and I'm worried that as soon as I add more than one, this query will become massively slow. SELECT count(*) FROM "exif_parse" WHERE (description ~* 'canon')

    Read the article

  • select row from table and substitute a field with one from another column if not null

    - by EarthMind
    I'm trying construct a PostgreSQL query that does the following but so far my efforts have been in vain. Problem: There are two tables: A and B. I'd like to select all columns from table A (having columns: id, name, description) and substitute the "A.name" column with the value of the column "B.title" from table B (having columns: id, table_A_id title, langcode) where B.table_A_id is 5 and B.langcode is "nl" (if there are any rows). I've tried using a CASE and COALESCE() but failed due to my inexperience with both concepts. Thanks in advance.

    Read the article

  • access: control source of textbox

    - by I__
    there is a form where a user enters a date in [Text4] when users clicks OK, the following code is run: DoCmd.OpenReport "All_Ones", acViewPreview the following is the control source of a textbox on the report [Forms]![By Number]![Text4] for some reason after the report is open, it just sayd #?nameor something like that, meaning that it is an invalid parameter. what am i doing wrong?

    Read the article

  • select row from table and substitute a field with one from another column if it exists

    - by EarthMind
    I'm trying construct a PostgreSQL query that does the following but so far my efforts have been in vain. Problem: There are two tables: A and B. I'd like to select all columns from table A (having columns: id, name, description) and substitute the "A.name" column with the value of the column "B.title" from table B (having columns: id, table_A_id title, langcode) where B.table_A_id is 5 and B.langcode is "nl" (if there are any rows). My attempts: SELECT A.name, case when exists(select title from B where table_A_id = 5 and langcode= 'nl') then B.title else A.name END FROM A, B WHERE A.id = 5 and B.table_A_id = 5 and B.langcode = 'nl' -- second try: SELECT COALESCE(B.title, A.name) as name from A, B where A.id = 5 and B.table_A_id = 5 and exists(select title from B where table_A_id = 5 and langcode= 'nl') I've tried using a CASE and COALESCE() but failed due to my inexperience with both concepts. Thanks in advance.

    Read the article

  • How to combine two rows and calculate the time difference between two timestamp values in MySQL?

    - by Nadar
    I have a situation that I'm sure is quite common and it's really bothering me that I can't figure out how to do it or what to search for to find a relevant example/solution. I'm relatively new to MySQL (have been using MSSQL and PostgreSQL earlier) and every approach I can think of is blocked by some feature lacking in MySQL. I have a "log" table that simply lists many different events with their timestamp (stored as datetime type). There's lots of data and columns in the table not relevant to this problem, so lets say we have a simple table like this: CREATE TABLE log ( id INT NOT NULL AUTO_INCREMENT, name VARCHAR(16), ts DATETIME NOT NULL, eventtype VARCHAR(25), PRIMARY KEY (id) ) Let's say that some rows have an eventtype = 'start' and others have an eventtype = 'stop'. What I want to do is to somehow couple each "startrow" with each "stoprow" and find the time difference between the two (and then sum the durations per each name, but that's not where the problem lies). Each "start" event should have a corresponding "stop" event occuring at some stage later then the "start" event, but because of problems/bugs/crashed with the data collector it could be that some are missing. In that case I would like to disregard the event without a "partner". That means that given the data: foo, 2010-06-10 19:45, start foo, 2010-06-10 19:47, start foo, 2010-06-10 20:13, stop ..I would like to just disregard the 19:45 start event and not just get two result rows both using the 20:13 stop event as the stop time. I've tried to join the table with itself in different ways, but the key problems for me seems to be to find a way to correctly identify the corresponding "stop" event to the "start" event for the given "name". The problem is exactly the same as you would have if you had table with employees stamping in and out of work and wanted to find out how much they actually were at work. I'm sure there must be well known solutions to this, but I can't seem to find them...

    Read the article

  • Left outer joins that don't return all the rows from T1

    - by Summer
    Left outer joins should return at least one row from the T1 table if it matches the conditions. But what if the left outer join performs a join successfully, then finds that another criterion is not satisfied? Is there a way to get the query to return a row with T1 values and T2 values set to NULL? Here's the specific query, in which I'm trying to return a list of candidates, and the user's support for those candidates IF such support exists. SELECT c.id, c.name, s.support FROM candidates c LEFT JOIN support s on s.candidate_id = c.id WHERE c.office_id = 5059 AND c.election_id = 92 AND (s.user_id = 2 OR s.user_id IS NULL) --This line seems like the problem ORDER BY c.last_name, c.name The query joins the candidates and support table, but finds that it's a different user who supported this candidate (user_id=3, say). Then the candidate disappears entirely from the result set.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 710 711 712 713 714 715 716 717 718 719 720 721  | Next Page >