LINQ: "Group Join" Functionality Joining Three Tables
Jul 21, 2010I'm working on becoming familiar with LINQ, and getting my head around the syntax and usage.
[Code]...
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Can't Use A Where Clause On Both Tables In A LINQ Group Join?
Jun 7, 2011Here's what I want to do:
Dim queryX = From m In db.Master
Where m.Field = value
Group Join d In db.Detail
On m.Id Equals d.MasterId Into Group
Where d.Field = value
In English, I want to join the master and detail tables, specifying conditions on each. But this causes the following compiler error:
"Name 'd' is either not declared or not in the current scope."
It works if I put this same condition in functional form:
Group Join d In db.Detail.Where(Function(x) x.Field = value)
but I think this is more typing, harder to understand, and introduces that irritating dummy variable. I really would prefer to use the query comprehension syntax. Is there a way to accomplish this?
Join Lists Or Arrays Like Outer Joining Tables In SQL?
Jun 27, 2011Basically what I'm having to do is create a program that takes a list of CaseIDs and compares them to a table on a remote SQL server. However, the table holding the CaseIDs on the remote server has nearly 120,000 records.
Currently my plan is to query all records on the remote server, save the query and the current list to tables in an Access DB file and then run an outer join to see which CaseIDs have no matching records on the remote server.
I believe this will be a much slower process than I would like. If I could load both queries into arrays or lists in VB and then compare them (therefore, not having to write 120,000 records to a DB file), it would be much faster.
.NET LINQ Group Joining?
Dec 2, 2010I have a list of object with 3 properties (quantity, service, name)I want to have all names and services in my list (kinda cross join) and the grouped quantity of the row corresponding. Not clear i guess
Quantity Service Name
3 Srv2 Bob
4 Srv2 Paul
2 Srv1 Paul
1 Srv2 Nick
I want as output All the services and all the names and corresponding quantities (0 if none)
Srv1 Paul 2
Srv1 Bob 0
Srv1 Nick 0
[code]....
Here is what I got so far, but I dont even get the expected resultsAnd I am acutally certain there is a pretty easy way of achieving what i want...
Dim services = (From a In interventions Select New With {.Service = a.Service}).Distinct()
Dim months = (From b In interventions Select New With {.Month = b.DateHeureIntervention.Month}).Distinct()
'Dim query = (From s In services _
[code]....
Datatables Left Join Linq - Joining 2 Datatables And Have The Joined Datatable As Result
Jun 1, 2012I'm having a hard time joining 2 datatables and have the joined datatable as result. First datatable (labels) holds data including a printerid. Second datatable (printers) holds printer references (id > unc). I would like to have as endresult (joined) a datatable with all data from the first datatable with the field (unc) of the second datatable. [Code]
View 3 RepliesLINQ To SQL And Join Two Tables With OR Clause
Apr 23, 2009Let's say I have Plans and Documents
Dim myPlans = _context.Plans.Where(predicate1)
Dim myDocuments = _context.Documents.Where(predicate2)
I have structured the where clause for each using PredicateBuilder. So, myPlans and myDocuments have a correct SQL statement. What I'd like to do is join these two tables into one linq statement. The problem I'm having is that, by default the AND condition is joining the where clauses.
myPlans Where clause : (p.name like "%test%" AND p.name like "%bed%") OR (p.description like "%test%" AND p.description like "%bed%")
myDocuments Where clause : (d.name like "%test%" AND d.name like "%bed%") OR (d.description like "%test%" AND d.description like "%bed%")
When I combine the two the desired result Where clause is:
Where (d.ID = p.ID) AND
(myplans where clause above) OR (mydocument where clause above). Meaning, I'd like the two where clauses in each of the tables to be "or" instead of "And".
The current result where clause is:
Where (d.ID = p.ID) AND
(myplans where clause above) AND (mydocument where clause above). Meaning, I'd like the two where clauses in each of the tables to be "or" instead of "And".
I'm forming the statement like this:
Dim test = From d in myDocuments _
Join p in MyPlans on d.ID Equals p.ID _
Select d.Name, p.Name
C# - LINQ To SQL Join 3 Tables And Select Multiple Columns And Also Using Sum
Aug 19, 2010I have three tables Student, TimeSheet and TimeRecord.
Talbe columns:
Student : StudentId, FirstName,
LastName
TimeSheet: TimeSheetId,StudentId, IsActive
[Code].....
LINQ Query - Join Tables On Nullable Columns
Apr 17, 2011How to JOIN tables on nullable columns? I have following LINQ-query, RMA.fiCharge can be NULL:
Dim query = From charge In Services.dsERP.ERP_Charge _
Join rma In Services.dsRMA.RMA _
On charge.idCharge Equals rma.fiCharge _
Where rma.IMEI = imei
Select charge.idCharge
I get a "Conversion from type 'DBNull' to type 'Integer' is not valid" in query.ToArray():
Dim filter = _
String.Format(Services.dsERP.ERP_Charge.idChargeColumn.ColumnName & " IN({0})", String.Join(",", query.ToArray))
So I could append a WHERE RMA.fiCharge IS NOT NULL in the query. But how to do that in LINQ or is there another option?
The problem was that the DataSet does not support Nullable-Types but generates an InvalidCastException if you query any NULL-Values on an integer-column. The modified LINQ-query from dahlbyk works with little modification. The DataSet generates a boolean-property for every column with AllowDbNull=True, in this case IsfiChargeNull.
Dim query = From charge In Services.dsERP.ERP_Charge _
Join rma In (From rma In Services.dsRMA.RMA _
Where Not rma.IsfiChargeNull
Select rma)
On charge.idCharge Equals rma.fiCharge _
Where rma.IMEI = imei
Select charge.idCharge
Join - Added Three Tables To A LINQ To SQL Class - Then Connected To The Data Sources
Jan 23, 2012I have three tables: BOOKS(BookID, Title, Author) CLASSES(ClassID, Title, MajorID,BookID) and MAJORS(MajorID, Description). I added these three tables to a LINQ to SQL class (UBooks.dbml) and then connected to the data sources. Then declared DataContext.
Using LINQ, my goal is to display all books in a grid which I have done with:
Dim allBooks = From Books In db.Books _
Order By Books.BookID _
Select Books
Me.BookBindingSource.DataSource = allBooks
Next I need to display all majors in a listbox. I would like the description to be shown however I am only getting the majorID to display with the code
lstMajors.DataSource = db.Majors
I have tried db.Majors.Description, however I am told then that Description is not a member of the LINQ table. and my final goal is to display all the books for whichever Major is selected in another data grid. This is what I am primarily concerned with right now. When using the SQLClient classes, I was able to create a string joining the tables (also had the description properly showing in the listbox, but that is of little importance right now to me). In the video tutorials I was able to watch whenever the tables were dragged from the database into the OR designer of the LINQtoSQL.dbml class file all of the associations were already there and the narrator only really had to do some drag and drop. Not only is drag and drop not working without these associations, but I'd much rather learn the code behind it.
Group Joins With Multiple Tables Converting SQL To Linq
Mar 7, 2011Can anyone help me by translating this SQL Statement to Linq? [code]
View 1 RepliesSql - Group By Having And Count As LINQ Query With Multiply Nested Tables?
Feb 28, 2012I have the following SQL query to return all Customers who have no OrderLines with no Parts assigned - i.e. I only want the customers within which every order line of every order has no parts assigned - (in the actual problem I am dealing with a different domain but have translated to customers/orders to illustrate the problem)
SELECT c.Customer_PK
FROM Customers c
INNER JOIN Orders o[code].....
This works but generates less than optimal SQL - it is doing a subquery for Count on each row of the customers query rather than using Group By and Having. I tried making the LINQ Group By syntax work but it kept putting the filter as a WHERE not a HAVING clause.Edit in response to Answers below: I am accepting JamieSee's answer as it addresses the stated problem, even though it does not produce the GROUP BY HAVING query I originally had.I am a VB developer so I have had a crack translating your code to VB, this is the closest I got to but it does not quite produce the desired output:
Dim qry = From c In context.Customers
Group Join o In context.Orders On c.Customer_PK Equals o.Customer_FK
Into joinedOrders = Group[cod].....
The problem I had is that I have to push "jl" into the Group By "Key" so I can reference it from the Where clause, otherwise the compiler cannot see that variable or any of the other variables appearing before the Group By clause.With the filter as specified I get all customers where at least one order has lines with no parts rather than only customers with no parts in any order.
C# - LINQ To SQL Join Two Tables To Select Parent Table Twice Based On Two Different Columns From Child Table?
Aug 23, 2010I have two tables Employees and CafeLogs. Some employees can be cashiers and also customers at the Cafe shop.
Table structures:
Employees: EmployeeId(PK) , FirstName, LastName
CafeLogs: LogId (PK), CashierId, EmployeeId, Value, => CashierId and EmployeeId are the data from column EmployeeId of Empoyee table
Table relationship:
Employees 1:N CafeLogs (CashierId (FK))
[code]....
Right now I know how to select only LogId, Employee's name, and , Value, not with Cashier name yet.
Dim query = From log In db.CafeLogs _
Join emp In db.Employees On emp.EmployeeId Equals log.EmployeeId _
Select log.LogId, emp.FirsName, emp.LastName, log.Value
Inner Join - Join Two Tables,'Employee' And 'Dispatch'
May 17, 2012Iwant to join two tables,'Employee' and 'Dispatch'. Dispatch has column 'DispatcherID' and 'TechnicianID' which are both foregn keys to EmployeeID in Employee table.I want to join these two tables using EmployeeID so that i can obtain the matching name to each id.but it only works when i make a single join to either DispatcherID or TechnicianID and not for both.
[code]
select Employee.firstname+' '+Employee,secondname as Technician,Employee.firstname+' '+Employee.secondname as Dispatcher from Dispatch inner join Employee on Dispatch.TechnicianID=Employee.EmployeeID inner join Employee on
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Update Tables Using Bindingnavigator Save Button From Join Tables
Oct 29, 2010In my datagridview I was fill in using join tables (table1 = pr_employees, table2 = pr_employee_deduction). My problem now is during save button I want to update records from table2 only.[code]
View 3 RepliesJoining Two SQL Server Tables Together
Jul 17, 2011I am not sure if the above title is suitable for what I mean, but basically my application has a login table with entry U_ID and I have also created another field in my other table which will store this ID from the login table.
What I want to do is, if a user with say U_ID = 1 downloads data and stores it in the
second table I would also for trackable reasons be able to store the U_ID of that user
in the second table so that I would know who downloaded the information.
How can I acheive this and if there are any example then point to them.
Joining Two Tables From Two Different Databases With VB.net, Possible?
Jun 5, 2012Can you perform a join on two tables, one is an Access database and the other is a SQL Server database.I understand that I could perform a SELECT on each database, and then manually join the results. Is this how I'm going to have to do it?
View 1 RepliesJoining Two Tables In The Dataset?
Apr 11, 2011I am having a data set in vb.net with two tables one table is filled by using oracle databse and another one from Sql 2005. How can we join these two tables in the dataset?
View 2 RepliesUpdate Datagrid Joining Two Tables With Bindingsource?
Oct 13, 2010I am trying to update a datagrid joining two tables with a bindingsource. I keep getting the following error: "dynamic sql generation is not supported against multiple base tables." Any ideas on how to fix the problem? Also, I realize that commandbuilder does not work for more than one table.
View 4 RepliesVS 2010 LINQ Sub-elements And Joining
Mar 30, 2012I'm really struggling with this. I have two XML files. The first one has items, and then sub elements for properties:
[Code]...
Joining LINQ Query Results For Each Item Together?
Feb 3, 2011In my application, I have a search query textbox (txtSearch) that works well with one-word queries with the following LINQ:[code]So how would I make the above query more generic (ie: able to handle any number of words in a query)?I should note that the object being queried is a List of strings pulled from an Access database. As it stands, this application only queries the database once and I'd like to keep it that way if possible.
View 3 Replies.net - Group Join With Multiple Conditions And One Of Them Being With A Constant?
Jan 29, 2010Here is a snippet of my (VB) LINQ:
From event_evn In xmlEvents.Descendants("event_evn") _
Join genre_gnr In xmlGenre.Descendants("genre_gnr") On event_evn.Element("evn_gnr_id") Equals genre_gnr.Element("gnr_id").Value _
Group Join eventdata_eda In xmlEventData.Descendants("eventdata_eda") On _
eventdata_eda.Element("eda_evn_id").Value Equals event_evn.Element("evn_id").Value And _
eventdata_eda.Element("eda_dty_id").Value Equals "15" _
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Pass A Parameter From The Select List Into A Function For Joining A Linq Query?
May 25, 2010I have a query that can be summarised in SQL as follows;
Select
S.StockCode
From
StockToCheck As S
[Code]....
Where the S var is a list of strings. This gives the error 'S' is not declared and points to the S in the function call / join (GetPOSStock). So it does not seem possible to do this in Linq, can anyone confirm?
How To Join Tables
Sep 1, 2010I've been using Java for a number of years, and now I'm at the beginning again with VB.NET.How would I go about joining two tables?- order doesn't matter, as long as i can print/display the order
Here's an example of what I'd like to do:
table 1
data 1 , data 2 , date time
12 , 23 , 2010/8/20 10:00:00
[code].....
SQL Join On Two Tables?
May 19, 2010I'm trying to do a join on two tables but i'm having a hard time. Here's the table schemes:
table1 : tbl_Trainees_IntentToParticipate
Scheme:
TraineeID (PK)
FName
LName
I want to select all TraineeID/FName/LNames from table1 where TakenTest (from table2)= false
heres the sql statement I have so far:
SqlJoinStatement = "SELECT tbl_Trainees_IntentToParticipate.FName, tbl_Trainees_IntentToParticipate.LName" _
& "FROM(tbl_Trainees_IntentToParticipate, tbl_Trainees_TabScores) " _
[code]....
Left Join / Group By And Sum Where Related Records Do Not Exist
Dec 9, 2010I am trying to accomplish the following:
SELECT Table1.prod_code, SUM(Table1.prod_bal) AS TotalProdBalance
FROM Table1
LEFT OUTER JOIN Table2 ON Table1.prod_code = Table2.prod_code
WHERE Table2.prod_code IS NULL
GROUP BY Table1.prod_code
HAVING (SUM(Table1.prod_bal) <> 0)
How to translate this to Linq using VB.net syntax?
.net - Ms-Access: Join 3 Tables?
May 23, 2009 how to join 3 tables, I have the following statement but I'm getting a missing a (syntax error "operator error")
da = New OleDbDataAdapter("SELECT [S].[Scheduled Vege], [V].[Description],
[DS].[Task], [DS].[Task Date], [DS].[Completed] FROM [Scheduled] AS S
INNER JOIN [Date Schedules] AS DS ON [S].[SchedID] = [DS].[SchedID]
[code]....
DB/Reporting :: Join Two Tables IN SQL?
Jun 16, 2010I am working on a Visual Basic 2008 program using an Access 2000 database. My SQL codereturns no records, but I know the table has a record. A simplified example of the code looks like this:
SELECT Table1.Field1, Table1.Field2, Table1.Field3, Table1.Field4, Table2. Field1, Table2.Field2 FROM Table1 INNER JOIN Table2 ON Table1.Field1 = Table2.Field1 AND Table1.Field2 = Table2.Field2 WHERE Table1.Field1=@Field1 AND Table1.Field2=@Field2;
[code].....
VS 2010 Join Tables From 2 Different DB's?
Nov 30, 2011Is it possible to join a table from a SQL Server DB and an oracle DB?
View 1 Replies.net - Join 2 Tables With A New Compute Field?
Mar 14, 2012here what i try to get:
Table A:
Field: Name A
Field: Id_A
[Code]....
In fact i want to list in grid the table A with a column which contains a checkbox and is checked if the item is include in table B (field TableA_Id_A).
Join 2 Tables From 2 Different Access Databases?
May 22, 2012I am tying to build a COMMAND that joins two tables from two different access databases in vb.net,
View 4 Replies