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  • MySQL Select Statement - Two Tables, Sort One Table by Count of Other Table

    - by Robert Boka
    So I have built a voting system for a custom post system i wrote. I want to be able to sort by "most voted", "Most liked", etc. I have two tables. Entry: ID, Title, Post Vote: ID, EntryID, Result I want to be able to query the vote table for each entry and see how many vote's there are, and then sort the entry's by how many vote's each table had. I have messed around with joins, etc. and cannot seem to figure it out. Any suggestions?

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  • sql query in the SqlDataAdapter()

    - by syedsaleemss
    Im using c# .net windows form application. I have loaded names of all the tables present in a database into a combobox. Now i need to display the contents of the selected table name. Normally we use SqlDataAdapter adp= new SqlDataAdapter("Select * from employee", con); This works fine. but instead of explicitly giving table name i.e employee i need to set it to combobox1.selected item. I have given like this its not working: string filename= combobox1.selecteditem; SqlDataAdapter adp= new SqlDataAdapter("Select * from filename", con); How can I select filename dynamically?

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  • How to retrieve last primary Id from mdb's table?

    - by William
    I got table with next columns: Id, Name, Age, Class I am trying to insert new row in db like this: INSERT INTO MyTable (Name, Age, Class) VALUES (@name, @age, @class) And get an exeption: "Index or primary key cannot contain a Null value." The question is how to add a new row without knowing next primary Id, or maybe there is a way to get this Id from the table with the help of another query ?

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  • How to get comma-separated values in Linq?

    - by Mujtaba Hassan
    I have the query below: var users = (from a in dc.UserRoles join u in dc.Users on a.intUserId equals u.ID join r in dc.Roles on a.intRoleId equals r.ID where r.intClientId == clientID select new UserRoleDetail { ID = a.ID, intUserId = a.intUserId, intRoleId = a.intRoleId, Name =u.FullName, //Here I need comma separated values. intAssignedById = a.intAssignedById, RoleName = r.vchName, Function = u.vchFunction }); I require all the values of "Name =u.FullName" to be comma-separated in a single record group by intRoleId. I mean for every role I need all the usernames in a sigle record comma separated. Any suggestion?

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  • Installing databases after installation of server.

    - by claws
    Hello, I my software I need the client to install a database server (MySQL in my case). I'm deploying the setup and making user install it like a pre-requisite. After installing the DBMS server. I need to setup databases (that I created) on the client machine. How to do this automatically (as part of installation.)?

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  • Optimize "not in" query

    - by Vasu
    Please help optimize this query: SELECT ts.SiteId, COUNT(ts.SiteId) AS Count FROM ts WHERE ts.SiteId not in (SELECT ts.SiteId FROM ts WHERE ts.uniqueid = 'xxx') GROUP BY ts.SiteId ORDER BY Count DESC

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  • Can MySQL reasonably perform queries on billions of rows?

    - by haxney
    I am planning on storing scans from a mass spectrometer in a MySQL database and would like to know whether storing and analyzing this amount of data is remotely feasible. I know performance varies wildly depending on the environment, but I'm looking for the rough order of magnitude: will queries take 5 days or 5 milliseconds? Input format Each input file contains a single run of the spectrometer; each run is comprised of a set of scans, and each scan has an ordered array of datapoints. There is a bit of metadata, but the majority of the file is comprised of arrays 32- or 64-bit ints or floats. Host system |----------------+-------------------------------| | OS | Windows 2008 64-bit | | MySQL version | 5.5.24 (x86_64) | | CPU | 2x Xeon E5420 (8 cores total) | | RAM | 8GB | | SSD filesystem | 500 GiB | | HDD RAID | 12 TiB | |----------------+-------------------------------| There are some other services running on the server using negligible processor time. File statistics |------------------+--------------| | number of files | ~16,000 | | total size | 1.3 TiB | | min size | 0 bytes | | max size | 12 GiB | | mean | 800 MiB | | median | 500 MiB | | total datapoints | ~200 billion | |------------------+--------------| The total number of datapoints is a very rough estimate. Proposed schema I'm planning on doing things "right" (i.e. normalizing the data like crazy) and so would have a runs table, a spectra table with a foreign key to runs, and a datapoints table with a foreign key to spectra. The 200 Billion datapoint question I am going to be analyzing across multiple spectra and possibly even multiple runs, resulting in queries which could touch millions of rows. Assuming I index everything properly (which is a topic for another question) and am not trying to shuffle hundreds of MiB across the network, is it remotely plausible for MySQL to handle this? UPDATE: additional info The scan data will be coming from files in the XML-based mzML format. The meat of this format is in the <binaryDataArrayList> elements where the data is stored. Each scan produces = 2 <binaryDataArray> elements which, taken together, form a 2-dimensional (or more) array of the form [[123.456, 234.567, ...], ...]. These data are write-once, so update performance and transaction safety are not concerns. My naïve plan for a database schema is: runs table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | start_time | TIMESTAMP | | name | VARCHAR | |-------------+-------------| spectra table | column name | type | |----------------+-------------| | id | PRIMARY KEY | | name | VARCHAR | | index | INT | | spectrum_type | INT | | representation | INT | | run_id | FOREIGN KEY | |----------------+-------------| datapoints table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | spectrum_id | FOREIGN KEY | | mz | DOUBLE | | num_counts | DOUBLE | | index | INT | |-------------+-------------| Is this reasonable?

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  • What is the Microsoft Query Syntax for Subqueries?

    - by Kuyenda
    I am trying to do a simple subquery join in Microsoft Query, but I cannot figure out the syntax. I also cannot find any documentation for the syntax. How would I write the following query in Microsoft Query? SELECT * FROM ( SELECT Col1, Col2 FROM `C:\Book1.xlsx`.`Sheet1$` ) AS a JOIN ( SELECT Col1, Col3 FROM `C:\Book1.xlsx`.`Sheet1$` ) AS b ON a.Col1 = b.Col1 Is there official documentation for Microsoft Query? Thanks!

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  • Trying to verify understanding of Foreign Keys MSSQL

    - by msarchet
    So I'm working on just a learning project to expose myself to doing some things I do not get to do at work. I'm just making a simple bug and case tracking app (I know there are a million this is just to work with some tools I don't get to). So I was designing my database and realized I've never actually used Foreign Keys before in any of my projects, I've used them before but never actually setting up a column as a FK. So I've designed my database as follows, which I think is close to correct (at least for the initial layout). However When I try to add the FK's to the linking Tables I get an error saying, "The tables present in the relationship must have the same number of columns". I'm doing this by in SQLSMS by going to the Keys 'folder' and adding a FK. Is there something that I am doing wrong here, I don't understand why the tables would have to have the same number of columns for me to add a FK relationship between the tables?

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  • Sql Query to get total rows and total rows matching specific condition

    - by mrNepal
    OK, Here is what my table looks like ------------------------------------------------ id type ----------------------------------------------- 1 a 2 b 3 a 4 c 5 c 7 a 8 a ------------------------------------------------ Now, I need a query that can give me this output... ----------------------------------------------------------------- count(*) | count(type=a) | count(type=b) | count(type=c) ----------------------------------------------------------------- 8 4 1 3 ------------------------------------------------------------------ I only know to get the total set using count(*), but how to do the remaining

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  • Postgesql select from 2 tables. Joins?

    - by Daniel
    I have 2 tables that look like this: Table "public.phone_lists" Column | Type | Modifiers ----------+-------------------+-------------------------------------------------------------------- id | integer | not null default nextval(('"phone_lists_id_seq"'::text)::regclass) list_id | integer | not null sequence | integer | not null phone | character varying | name | character varying | and Table "public.email_lists" Column | Type | Modifiers ---------+-------------------+-------------------------------------------------------------------- id | integer | not null default nextval(('"email_lists_id_seq"'::text)::regclass) list_id | integer | not null email | character varying | I'm trying to get the list_id, phone, and emails out of the tables in one table. I'm looking for an output like: list_id | phone | email ---------+-------------+-------------------------------- 0 | | [email protected] 0 | | [email protected] 0 | | [email protected] 0 | | [email protected] 0 | | [email protected] 1 | 15555555555 | 1 | 15555551806 | 1 | 15555555508 | 1 | 15055555506 | 1 | 15055555558 | 1 | | [email protected] 1 | | [email protected] I've come up with select pl.list_id, pl.phone, el.email from phone_lists as pl left join email_lists as el using (list_id); but thats not quite right. Any suggestions?

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  • How to convert full outer join query to O-R query?

    - by Kugel
    I'm converting relational database into object-relational in Oracle. I have a query that uses full outer join in the old one. Is it possible to write the same query for O-R database without explicitly using full outer join? For normal inner join it simple, I just use dot notation together with ref/deref. I'm interested in this in general so let's say the relational query is: select a.attr, b.attr from a full outer join b on (a.fk = b.pk); I want to know if it's a good idea to do it this way: select a.attr, b.attr from a_obj a full outer join b_obj b on (a.b_ref = ref(b));

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  • MySQL query using multiple criteria from checkboxes

    - by jungle_programmer
    I would like to do a multiple search query usig multiple checkboxes which represent particular textboxes. How do i create a mysql query which will be filtering the checked and unchecked checkboxes (probably using if statements)? The query should be able to filter the checked and ucnchecked boxes and query them using the AND condition. Thanks

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  • How do I find the user that has both a cat and a dog?

    - by brad
    I want to do a search across 2 tables that have a many-to-one relationship, eg class User << ActiveRecord::Base has_many :pets end class Pet << ActiveRecord::Base belongs_to :users end Now let's say I have some data like so users id name 1 Bob 2 Joe 3 Brian pets id user_id animal 1 1 cat 2 1 dog 3 2 cat 4 3 dog What I want to do is create an active record query that will return a user that has both a cat and a dog (i.e. user 1 - Bob). My attempt at this so far is User.joins(:pets).where('pets.animal = ? AND pets.animal = ?','dog','cat') Now I understand why this doesn't work - it's looking for a pet that is both a dog and a cat so returns nothing. I don't know how to modify this to give me the answer I want however. Does anyone have any suggestions? This seems like it should be easy - it doesn't seem like an especially unusual situation.

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  • How Optimize sql query make it faster

    - by user502083
    Hello every one : I have a very simple small database, 2 of tables are: Node (Node_ID, Node_name, Node_Date) : Node_ID is primary key Citation (Origin_Id, Target_Id) : PRIMARY KEY (Origin_Id, Target_Id) each is FK in Node Now I write a query that first find all citations that their Origin_Id has a specific date and then I want to know what are the target dates of these records. I'm using sqlite in python the Node table has 3000 record and Citation has 9000 records, and my query is like this in a function: def cited_years_list(self, date): c=self.cur try: c.execute("""select n.Node_Date,count(*) from Node n INNER JOIN (select c.Origin_Id AS Origin_Id, c.Target_Id AS Target_Id, n.Node_Date AS Date from CITATION c INNER JOIN NODE n ON c.Origin_Id=n.Node_Id where CAST(n.Node_Date as INT)={0}) VW ON VW.Target_Id=n.Node_Id GROUP BY n.Node_Date;""".format(date)) cited_years=c.fetchall() self.conn.commit() print('Cited Years are : \n ',str(cited_years)) except Exception as e: print('Cited Years retrival failed ',e) return cited_years Then I call this function for some specific years, But it's crazy slowwwwwwwww :( (around 1 min for a specific year) Although my query works fine, it is slow. would you please give me a suggestion to make it faster? I'd appreciate any idea about optimizing this query :) I also should mention that I have indices on Origin_Id and Target_Id, so the inner join should be pretty fast, but it's not!!!

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  • drop down list binding

    - by John
    I have a table which has an Id and a name field. I usually bind the name to the dropdownlist but I was told that any dml should be on the Id so how can I use the name in the dropdownlist and at the same time still use the Id?

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  • alias some columns names as one field in oracle's join select query

    - by Marecky
    Hi We are developing something like a social networking website. I've got task to do 'follow me' functionality. In our website objects are users, teams, companies, channels and groups (please don't ask why there are groups and teams - it is complicated for me too, but teams are releated to user's talent) Users, teams, channels, companies and groups have all their own tables. I have a query which gets me all the follower's leaders like this select --fo.leader_id, --fo.leader_type, us.name as user_name, co.name as company_name, ch.title as channel_name, gr.name as group_name, tt.name as team_name from follow_up fo left join users us on (fo.leader_id = us.id and fo.leader_type = 'user') left join companies co on (fo.leader_id = co.user_id and fo.leader_type = 'company') left join channels ch on (fo.leader_id = ch.id and fo.leader_type = 'channel') left join groups gr on (fo.leader_id = gr.id and fo.leader_type = 'group') left join talent_teams tt on (fo.leader_id = tt.id and fo.leader_type = 'team') where follower_id = 83 I need to get all fields like: user_name, company_name, channel_name, group_name, team_name as one field in SELECT's product. I have tried to alias them all the same 'name' but Oracle numbered it. Please help :)

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  • Bizarre WHERE col = NULL behavior

    - by Kenneth
    This is a problem one of our developers brought to me. He stumbled across an old stored procedure which used 'WHERE col = NULL' several times. When the stored procedure is executed it returns data. If the query inside the stored procedure is executed manually it will not return data unless the 'WHERE col = NULL' references are changed to 'WHERE col IS NULL'. Can anyone explain this behavior?

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  • What are the Pros and Cons of Cascading delete and updates?

    - by Misnomer
    Hi, Maybe this is sort of a naive question...but I think that we should always have cascading deletes and updates. But I wanted to know are there problems with it and when should we should not do it? I really can't think of a case right now where you would not want to do an cascade delete but I am sure there is one...but what about updates should they be done always? So can anyone please list out the pros and cons of cascading deletes and updates ? Thanks.

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