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 691/1630 | < Previous Page | 687 688 689 690 691 692 693 694 695 696 697 698  | Next Page >

  • how to combine the related version in group by

    - by randeepsp
    select count(a),b,c from APPLE join MANGO on (APPLE.link=MANGO.link) join ORANGE on (APPLE.link=ORANGE.link) where id='camel' group by b,c; the column b gives values like 1.0 1.0,R 1.0,B 2.0 2.0,B 2.0,R 3.0,C 3.0,R is there a way to modify the above quer so that all 1.0 and 1.0,R and 1.0,B are merged as 1.0 and 2.0,2.0,B are merged as 2.0 and same way for 3.0 and 4.0

    Read the article

  • Select 2 Rows from Table when COUNT of another table

    - by Marcus
    Here is the code that I currently have: SELECT `A`.* FROM `A` LEFT JOIN `B` ON `A`.`A_id` = `B`.`value_1` WHERE `B`.`value_2` IS NULL AND `B`.`userid` IS NULL ORDER BY RAND() LIMIT 2 What it currently is supposed to do is select 2 rows from A when the 2 rows A_id being selected are not in value_1 or value_2 in B. And the rows in B are specific to individual users with userid. What I need to do is make it also so that also checks if there are already N rows in B matching a A_id (either in value_1, or value_2) and userid, and if there are more than N rows, it doesn't select the A row.

    Read the article

  • Does Table.InsertOnSubmit create a copy of the original table?

    - by Bryan
    Using InsertOnSubmit seems to have some memory overhead. I have a System.Data.Linq.Table<User> table. When I do table.InsertOnSubmit(user) and then int count = table.Count(), the memory usage of my application increases by roughly the size of the User table, but the count is the number of items before user was inserted. So I'm guess an enumeration after InsertOnSubmit will create a copy of the table. Is that true?

    Read the article

  • Select *, max(date) works in phpMyAdmin but not in my code

    - by kdobrev
    OK, my statement executes well in phpMyAdmin, but not how I expect it in my php page. This is my statement: SELECT egid , group_name , limit , MAX( date ) FROM employee_groups GROUP BY egid ORDER BY egid DESC ; This is may table: CREATE TABLE employee_groups ( egid int(10) unsigned NOT NULL, date date NOT NULL, group_name varchar(50) NOT NULL, limit smallint(5) unsigned NOT NULL, PRIMARY KEY (egid,date) ) ENGINE=MyISAM DEFAULT CHARSET=cp1251; I want to extract the most recent list of groups, e.g. if a group has been changed I want to have only the last change. And I need it as a list (all groups).

    Read the article

  • Best way to model Customer <--> Address

    - by Jen
    Every Customer has a physical address and an optional mailing address. What is your preferred way to model this? Option 1. Customer has foreign key to Address Customer (id, phys_address_id, mail_address_id) Address (id, street, city, etc.) Option 2. Customer has one-to-many relationship to Address, which contains a field to describe the address type Customer (id) Address (id, customer_id, address_type, street, city, etc.) Option 3. Address information is de-normalized and stored in Customer Customer (id, phys_street, phys_city, etc. mail_street, mail_city, etc.) One of my overriding goals is to simplify the object-relational mappings, so I'm leaning towards the first approach. What are your thoughts?

    Read the article

  • Does normalization really hurt performance in high traffic sites?

    - by Luke101
    I am designing a database and I would like to normalize the database. I one query I will joining about 30-40 tables. Will this hurt the website performance if it ever becomes extremely popular? This will be the main query and it will be getting called 50% of the time. The other queries I will be joining about 2 tables. I have a choice right now to normalize or not to normalize but if the normalization becomes a problem in the future i may have to rewrite 40% of the software and it may take me a long time. Does normalization really hurt in this case? Should I denormalize now while I have the time?

    Read the article

  • Question about Transact SQL syntax

    - by Yousui
    Hi guys, The following code works like a charm: BEGIN TRY BEGIN TRANSACTION COMMIT TRANSACTION END TRY BEGIN CATCH IF @@TRANCOUNT > 0 ROLLBACK; DECLARE @ErrorMessage NVARCHAR(4000), @ErrorSeverity int; SELECT @ErrorMessage = ERROR_MESSAGE(), @ErrorSeverity = ERROR_SEVERITY(); RAISERROR(@ErrorMessage, @ErrorSeverity, 1); END CATCH But this code gives an error: BEGIN TRY BEGIN TRANSACTION COMMIT TRANSACTION END TRY BEGIN CATCH IF @@TRANCOUNT > 0 ROLLBACK; RAISERROR(ERROR_MESSAGE(), ERROR_SEVERITY(), 1); END CATCH Why?

    Read the article

  • Database Design Question: GUID + Natural Numbers

    - by Alan
    For a database I'm building, I've decided to use natural numbers as the primary key. I'm aware of the advantages that GUID's allow, but looking at the data, the bulk of row's data were GUID keys. I want to generate XML records from the database data, and one problem with natural numbers is that I don't want to expose my database key's to the outside world, and allow users to guess "keys." I believe GUID's solve this problem. So, I think the solution is to generate a sparse, unique iD derived from the natural ID (hopefully it would be 2-way), or just add an extra column in the database and store a guid (or some other multibyte id) The derived value is nicer because there is no storage penalty, but it would be easier to reverse and guess compared to a GUID. I'm (buy) curious as to what others on SO have done, and what insights they have.

    Read the article

  • Removal of table primary key in MySQL

    - by marionmaiden
    Hello, I've removed the primary key of one table of my MySQL database, but now, when I use the MySQL Administrator and try to edit some data of this table, it doesn't allow me to do this. The button edit that appears in the bottom of the table keeps visible, but disabled to click.

    Read the article

  • Does anybody have any suggestions on which of these two approaches is better for large delete?

    - by RPS
    Approach #1: DECLARE @count int SET @count = 2000 DECLARE @rowcount int SET @rowcount = @count WHILE @rowcount = @count BEGIN DELETE TOP (@count) FROM ProductOrderInfo WHERE ProductId = @product_id AND bCopied = 1 AND FileNameCRC = @localNameCrc SELECT @rowcount = @@ROWCOUNT WAITFOR DELAY '000:00:00.400' Approach #2: DECLARE @count int SET @count = 2000 DECLARE @rowcount int SET @rowcount = @count WHILE @rowcount = @count BEGIN DELETE FROM ProductOrderInfo WHERE ProductId = @product_id AND FileNameCRC IN ( SELECT TOP(@count) FileNameCRC FROM ProductOrderInfo WITH (NOLOCK) WHERE bCopied = 1 AND FileNameCRC = @localNameCrc ) SELECT @rowcount = @@ROWCOUNT WAITFOR DELAY '000:00:00.400' END

    Read the article

  • HQL 'parsename' equivalent

    - by jaume
    I've discovered PARSENAME function as a good choice to order IP address stored in Database. Here there is an example. My issue is I'm using Hibernate with named queries in a xml mapping file and I am trying to avoid the use of session.createSQLQuery(..) function. I'm wondering if exists any PARSENAME equivalent function for HQL queries. I'm searching for it and cannot find anything. Many thanks.

    Read the article

  • Passing a outside variable into a <asp:sqldatasource> tag. ASP.NET 2.0

    - by MadMAxJr
    I'm designing some VB based ASP.NET 2.0, and I am trying to make more use of the various ASP tags that visual studio provides, rather than hand writing everything in the code-behind. I want to pass in an outside variable from the Session to identify who the user is for the query. <asp:sqldatasource id="DataStores" runat="server" connectionstring="<%$ ConnectionStrings:MY_CONNECTION %>" providername="<%$ ConnectionStrings:MY_CONNECTION.ProviderName %>" selectcommand="SELECT THING1, THING2 FROM DATA_TABLE WHERE (THING2 IN (SELECT THING2 FROM RELATED_DATA_TABLE WHERE (USERNAME = @user)))" onselecting="Data_Stores_Selecting"> <SelectParameters> <asp:parameter name="user" defaultvalue ="" /> </SelectParameters> </asp:sqldatasource> And on my code behind I have: Protected Sub Data_Stores_Selecting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.SqlDataSourceSelectingEventArgs) Handles Data_Stores.Selecting e.Command.Parameters("user").Value = Session("userid") End Sub Oracle squaks at me with ORA-01036, illegal variable name. Am I declaring the variable wrong in the query? I thought external variables share the same name with a @ prefixed. from what I understand, this should be placing the value I want into the query when it executes the select. EDIT: Okay, thanks for the advice so far, first error was corrected, I need to use : and not @ for the variable declaration in the query. Now it generates an ORA-01745 invalid host/bind variable name. EDIT AGAIN: Okay, looks like user was a reserved word. It works now! Thanks for other points of view on this one. I hadn't thought of that approach.

    Read the article

  • Deleting rows from different tables

    - by Ross
    Here is what i'm trying to do: Delete the project from projects table and all the images associated with that project in the images table Lets say $del_id = 10 DELETE FROM projects, images WHERE projects.p_id = '$del_id' AND images.p_id = '$del_id' What is wrong with this query

    Read the article

  • how to write this query using joins?

    - by aquero
    Hi, i have a table campaign which has details of campaign mails sent. campaign_table: campaign_id campaign_name flag 1 test1 1 2 test2 1 3 test3 0 another table campaign activity which has details of campaign activities. campaign_activity: campaign_id is_clicked is_opened 1 0 1 1 1 0 2 0 1 2 1 0 I want to get all campaigns with flag value 3 and the number of is_clicked columns with value 1 and number of columns with is_opened value 1 in a single query. ie. campaign_id campaign_name numberofclicks numberofopens 1 test1 1 1 2 test2 1 1 I did this using sub-query with the query: select c.campaign_id,c.campaign_name, (SELECT count(campaign_id) from campaign_activity WHERE campaign_id=c.id AND is_clicked=1) as numberofclicks, (SELECT count(campaign_id) from campaign_activity WHERE campaign_id=c.id AND is_clicked=1) as numberofopens FROM campaign c WHERE c.flag=1 But people say that using sub-queries are not a good coding convention and you have to use join instead of sub-queries. But i don't know how to get the same result using join. I consulted with some of my colleagues and they are saying that its not possible to use join in this situation. Is it possible to get the same result using joins? if yes, please tell me how.

    Read the article

  • about Select statement !

    - by user329820
    hi, I have read that after select we use column-names but I have found a statement that was like this: SELECT 'A' FROM T WHERE A = NULL; would you lease help me? thanks (A is a column- name here?) my DBMS is MySQL

    Read the article

  • Should I use DATE and TIME as fields rather than DATETIME

    - by whitstone86
    I have a project on going for a TV guide, called mytvguide in the database - I use PHPMyAdmin. This is the structure for one table, which is called tvshow1: Field Type channel varchar(255) date date No airdate time No expiration time No episode varchar(255) setreminder varchar(255) but am not sure how to get DATE, TIME to work with the pagination script (below is the script, which works for the version with DATETIME): http://pastebin.com/6S1ejAFJ However, although the DATETIME one works - it shows programmes that air on the day itself like this: Programme 1 showing on Channel 1 2:35pm "Episode 2" Set Reminder Programme 1 showing on Channel 1 May 26th - 12:50pm "Episode 3" Set Reminder Programme 1 showing on Channel 1 May 26th - 5:55pm "Episode 3" Set Reminder but I'm not quite sure how to replicate that for the fields that use DATE, TIME functions as seen above. Any advice on this is appreciated, thanks!

    Read the article

  • How to store MySQL query results in another Table?

    - by Taz
    How to store results from following query into another table. Considering there is an appropriate table already created. SELECT labels.label,shortabstracts.ShortAbstract,images.LinkToImage,types.Type FROM ner.images,ner.labels,ner.shortabstracts,ner.types WHERE labels.Resource=images.Resource AND labels.Resource=shortabstracts.Resource AND labels.Resource=types.Resource;

    Read the article

  • How do I do proximity search in Oracle right?

    - by hko19
    Oracle's NEAR operator for full text search returns a score based on the proximity of two or more query terms. For example: near((dog, bite), 6) matches if 'dog' and 'bite' occurs within 6 words. What if I'd like it to match if either 'dog' or 'cat' or any other type of animal occurs within 6 words of the word 'bite'? I tried: near(((dog OR cat OR animal), bite), 6) but I got: NEAR operand not a phrase, equivalence or another NEAR expression Rather than expanding all possible combination into multiple NEAR and 'or' them together, what is the proper way to write such query?

    Read the article

  • SQLException: incorrect syntax near '2'.

    - by Tobechukwu Ezenachukwu
    whenever I call the "ExecuteNonQuery" command on the following CommandText, I get the above SQLException myCommand.CommandText = "INSERT INTO fixtures (round_id, matchcode, date_utc, time_utc, date_london, time_london, team_A_id, team_A, team_A_country, team_B_id, team_B, team_B_country, status, gameweek, winner, fs_A, fs_B, hts_A, hts_B, ets_A, ets_B, ps_A, ps_B, last_updated) VALUES (" _ & round_id & "," & match_id & "," & date_utc & ",'" & time_utc & "'," & date_london & ",'" & time_london & "'," & team_A_id & ",'" & team_A_name & "','" & team_A_country & "'," & team_B_id & ",'" & team_B_name & "','" & _ team_B_country & "','" & status & "'," & gameweek & ",'" & winner & "'," & fs_A & "," & fs_B & "," & hts_A & "," & hts_B & "," & ets_A & "," & ets_B & "," & ps_A & "," & ps_B & "," & last_updated & ")" But whenever, i remove the last table item - "last_updated", the error disappears. Please help me resolve this issue. Is there any special treatment to be given to datetime fields??? Thanks for your help

    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 | 687 688 689 690 691 692 693 694 695 696 697 698  | Next Page >