C# - Selecting Multiple Distinct Values In Database?
Sep 27, 2010
I have this online quiz that generates random questions, but the only problem is that it repeats the previous questions. I have limited questions (I have 10 questions in my table, but I have limited the number of questions to be 5. The output would only display 5 random questions) which I named as RequiredRecords.
question_id
1
3
4
[code].....
I have tried to visit this question, but it doesn't resolve my problem. Below is some of my code and SQL statements I used.
I figured out that there's nothing wrong with my query on creating random questions and I can display it with no duplication, but there's something wrong with my other codes that makes the program having a duplication.
Code Behind using VS2008 3.5
Partial Class Student_DetailView
Inherits System.Web.UI.Page
Shared TotalRecords As Integer
Dim objConnection As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source = C:DB.mdb;Jet OLEDB:Database Password=Pass1;") Dim objdataadapter As New OleDbDataAdapter("SELECT DISTINCT LOCATION FROM Table", objConnection)
I have a DataTable with about 64 columns, including "UserAnswer", "CorrectAnswer", and "QID_Lookup". I am building a LINQ that will select all the rows that have a correct answer (user answer matches correct answer), but I only want to select rows that have distinct "QID_Lookup".
[Code]...
The problem is that the result set includes duplicate QID_Lookup values. How can I include only distinct QID_Lookup values? keep in mind that there are 64 columns, so if I can avoid it, I wouldn't want to list each column individually for selection.
I have a three column table which lists every person, every event they may have attended, and what percentage of the time they were there. I would really like to display this on one page with the person names on the side and the event names across the top.
Here' an example of what I have:
NAME EVENT %ATTENDANCE Smith Rock Climbing 50 Allen Rock Climbing 78
I am using strongly typed dataset and have many tables in that. The problem is now I want to filter data from GetData() function which has a query like select * from table_name
How can I filter a particular table and distinct values from it. Also if I try to filter it return all column but rest have null values except the one I asked, so I cannot assign it as a datasource to a datagrid or combobox. How can I do this..
I have a database which need to be assigned into array arr()(), e.g.
arr(0)(0) = aa arr(1)(0) = ab arr(2)(0) = aa arr(0)(1) = bb arr(1)(1) = ba arr(2)(1) = ba arr(0)(2) = cc arr(1)(2) = cc arr(2)(2) = cc
I need to find distinct / unique value in each arr(k)(0), arr(k)(1), arr(k)(2); where k=0..2. Then i need to insert the result into array cat as follows:
I've tried code below but it doesn't work. The assigning process into array arr()() from DB is OK. Problem only come up if I try to find the distinct value (If Not (cat(j).Contains(ds.Tables(0).Rows(i).Item(j))) ... End If).
For i = 0 To 2 list(i) = New Integer(3) {} For j = 0 To 2
Im having trouble getting the sum of a "Status Column" It is unbound. It has 2 Items "Active and Inactive" I would like to have lblInact.Text to show the total of Inactives of that column.
Dim viewdata2 As DataView = fxts.fxtsdata.Tables("clients").DefaultView Dim viewsorted2 As DataTable = viewdata2.ToTable("clients", True, "Surname", "Name")
Supposing the referenced List below contains 2 elements: Dim Countries = From c In List _ Select New With { .Country = c.Country, .CountryID = c.CountryID }
I have a "result" which is DataTable and I like to get the x distinct values(City) and convert it back to DataTable how do I do this the code below gives me an error
Dim query = (From x In results.AsEnumerable() Select (x.Field(Of String)("City"))).Distinct().CopyToDataTable()
so what I want is records of distinct cities I can get that but the problem I am having is converting it back to Datable.
Edited:I am using "where" in this statement and it does convert to Table(works fine) but not on "select"
Dim results = (From myRow In ds.Tables(1).AsEnumerable() Where (myRow.Field(Of String)("xxxx") = xxxx) Select myRow).Distinct().CopyToDataTable()
I have a DataTable that has several hundred rows.I want to get a row count of distinct values in a particular column.For example, I have a DataTable of Product Orders, but I want to get the number of unique Customers.
I was using this code, but I can't rely on it because my binding source is filtered from time to time.If my binding source has filtered out all rows datatable.DefaultView returns 0 rows.
I have a datatable which has been dynamically generated from FoxPro tables using a UNION Select statement. e.g.SELECT * FROM x UNION SELECT * FROM y UNION SELECT * FROM Z ORDER By v_alue1This produces a datatable with about 100 rows, each containing many fields, one of which is c_olor. From this datatable, I would like to select the distinct colors and then output in a dropdown.I have a public class Color which just has one property which I can then use as the DataTextField and DataValueField for the dropdownlist
Public Class Color Private _c_olor As String Public Property c_olor() As String
I have a combox and a datagridview on a form, the combox filters the datagridview but doesnt have Distinct values. I found this on one of your post. I have a Products DB Table with ProductID, Series, Description and UnitPrice, I am trying to filter the the datagrid using the column Series with the combobox but i get multiple values of the same thing in the combobox, where i would like to make it Distinct.[code]
I load a list from a database like the example below. The class has more properties that the database table holds so when I load the list from the DB, there are Null values for certain properties of each item in the list. When I try List = List.Distinct.ToList, it never works (when null values are present).
I have an EnumerableRowCollection that looks like the following: VendorCode | GroupType | Variance 01165 G .16 01165 G .16 01165 CH .16 01165 CH .18 07754 G .25 07754 G .25 07754 G .39
Essentially, this is a massive list of vendor codes, their groups, and price variances. I need to compose a query that will create a distinct list vendor codes and group types. The catch, however, is that I need to evaluate all of the variances associated with that particular VendorCode/GroupType to see if they are all the same - it they are not, I need to return some way of signifying that the group has a "custom" variance, otherwise it needs to return the value (ie: if they are all .16, then return .16, if there are multiple values, return "custom")
The result would look like this, based off of the list I showed above. VendorCode | GroupType | Variance 01165 G .16 01165 CH custom 07754 G custom
I have no trouble getting a distinct list of VendorCode/GroupType - this is what I have so far: Dim distinctList = From q In query Select q.VendorCode, q.GroupType, (evaluated q.Variance here?) Distinct (where "query" is an EnumerableRowCollection(Of (anonymous type))) I'm at a loss, though, on how to evaluate the variance property to get the result that I need?
I have three dropdownlist which values are to be inserted in one particular field in the database. But i am new to ASP.
This are my following codes: Dim strConn = ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString Dim myConn As New SqlConnection(strConn)
