linq join returning duplicates

Since no primary key is set on a view, it simply took the first column in the table. Read more of Matthew Mombrea's ByteStream blog and follow Matt on Twitter (@mombrea) and Google+. This gets just a little more complex to satisfy, but it can be satisfied. After spending a few months living there and frequent return trips, Costa Rica has become my home away from home. Why is there no 'pas' after the 'ne' in this negative sentence? Improving time to first byte: Q&A with Dana Lawson of Netlify, What its like to be on the Python Steering Council (Ep. The type of the keys returned by the key selector functions. Depends on what exact purpose your function serves. Provide an answer or move on to the next question. Is it better to use swiss pass or rent a car? For the latest IT news, analysis and how-tos, follow ITworld on Twitter and Facebook. So EF Core generates a . Copyright 2013 IDG Communications, Inc. SQL SELECT distinct GL.LEDTYP_0 AS 'Ledger Type' , GL.LED_0 AS 'Ledger_Code' , GL.FIY_0 AS Fiscal_Year, GL.CPY_0 AS 'Company_Code' , GL.PER_0 AS PERIOD FROM [SEI_LIVE]. The DISTINCT keyword will return only unique rows from the result set. In this example, that type is an anonymous type that consists of the Person.FirstName and Pet.Name properties for each matching pair. The type of the elements of the second sequence. Last, notice that even when having the Where condition this will return an IEnumerable<> of results. How high was the Apollo after trans-lunar injection usually? The following example shows you how to implement an inner join by using a group join. The reason this is happening is that the Entity Framework has attempted to identify a unique primary key on the view when you added the view object to your .edmx file. The join operation compares these composite keys for equality and returns pairs of objects from each list where both the first name and the last name match. Linq query return duplicate record from SQL database What exactly is going on inside? Asking for help, clarification, or responding to other answers. The select clause in C# defines how the resulting objects will look. It's basically the same, but I cannot have it do a select distinct. What would naval warfare look like if Dreadnaughts never came to be? If you would like to change your settings or withdraw consent at any time, the link to do so is in our privacy policy accessible from our home page.. Entity Framework Core (EF Core) is a ground-up rewrite of Microsoft's object-database mapping framework. Country has 0..1 to * relationship with leagues. In query expression syntax, a join (C#) or Join (Visual Basic) clause translates to an invocation of Join. Here's my BAQ with a Left outer join from Part to VendPart based off "Company" and "PartNum". February 23, 2021 In this post, we'll look at some pitfalls and ideas EF Core users like yourself may want to consider when developing an application. I tried using Distinct with no luck. Usage is simple: A join refers to the operation of correlating the elements of two sources of information based on a common key. 9,669 39 140 253 Maybe try adding .ToList () on the end of the query you're assigning to leagues. Do the subject and object have to agree in number? Linq Lambda join returning duplicate records How to remove an string object from a list? If your data doesn't have a primary key, AsNoTracking () is the simplest way to resolve this and you don't lose anything as since you don't update view records you don't need EF to ever track this data. to no avail. Perform inner joins (LINQ in C#) | Microsoft Learn Merge duplicate data without affecting others in LINQ code. Unlike a non-group join, which would produce a pair of elements for each match, the group join produces only one resulting object for each element of the first collection, which in this example is a Person object. Join brings the two information sources and the keys by which they are matched together in one method call. The second option is to add a pseudo key to your view. LINQ method to join every n elements in a series by a function, and then re-aggregate those results into a new list? Depending on your use case, you can choose INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN. The default value for a reference type is null; therefore, the example checks for a null reference before accessing each element of each Pet collection. Correlates the elements of two sequences based on matching keys. +1 (416) 849-8900, Ignify.Framework.Data.Tables.PMItemPriceList_AX. To learn more, see our tips on writing great answers. spelling and grammar. In LINQ, I make a simple call to the same view: var results = dataContainer.MyViewName.ToList (); The result set that is returned from that call looks like this: As you can see, the correct. Archived Forums I-L > LINQ Project General Question 0 Sign in to vote Hi all, I have a many to many relationship between Car and Driver with a cross-reference table named Driver_Car. Youll be auto redirected in 1 second. C# LINQ do have a Distinct () method that works on simple types: 1 2 3 4 5 6 7 8 9 10 11 // An string with non-unique elements string s = "a|b|c|d|a"; var distinctList = s.Split ('|').Distinct ().ToArray (); var distinctString = string.Join ("|", distinctList); // Output will be: "a|b|c|d" Console.WriteLine (distinctString); outer or inner or outerKeySelector or innerKeySelector or resultSelector is null. Instead of correlating elements based on just one property, you can use a composite key to compare elements based on multiple properties. I thought "join" meant left join, meaning only matches in the left table, Linq Lambda join returning duplicate records, ADO.NET, Entity Framework, LINQ to SQL, Nhibernate. The following example performs a group join of objects of type Person and Pet based on the Person matching the Pet.Owner property. The first is that you can simply add a column to your view select statement which is unique. GROUP BY b.Id, a.OtherId [Solved]-Linq join returning duplicate results-LINQ,C# score:3 Accepted answer To do so you need to use GroupJoin: Notice the addition of the into at the end of the join Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, See the top related question to this question -. The query uses the join clause in C# to match Person objects with Pet objects whose Owner is that Person. This differs from the use of SelectMany, which requires more than one method call to perform the same operation. None. More info about Internet Explorer and Microsoft Edge. A multiple join in which successive join operations are appended to each other. This method causes the query to be executed immediately. The content must be between 30 and 50000 characters. There are two overloaded versions available for the LINQ Except Method in C#. An inner join that correlates elements from two data sources based on a composite key. According to your description and data table, I create two simple data tables. Data access layer or business logic layer? so would I put that new class in my data access layer, or my business logic layer? How to create a mesh of objects circling a sphere. To learn more, see our tips on writing great answers. Perform grouped joins (LINQ in C#) | Microsoft Learn If comparer is null, the default equality comparer, Default, is used to hash and compare keys. In Entity Framework Core you can use the Join () and GroupJoin () method to achieve the same results. Complex Query Operators - EF Core | Microsoft Learn Don't tell someone to read the manual. An inner join that correlates elements from two data sources based on a composite key. To do this, specify the key selector function for each collection to return an anonymous type that consists of the properties you want to compare. That means the SelectMany Projection Method combines the records from a sequence of results and then converts it into one result. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. @Wuzi - Did this solution help you solve your problem? BAQ - Select Distinct - ERP 10 - Epicor User Help Forum 1 solution Solution 1 well it's hard to say. Note that method syntax must be used here. Querying the view returns the expected results. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. How can I code an outer join using LINQ and EF6? I'd like it to only return one row regardless of how many times "Cost center" matchesfound in the Services table. If you define your own type for the query, you can return a list of those. A composite key, which is a key that consists of more than one value, enables you to correlate elements based on more than one property. The query represented by this method is not executed until the object is enumerated either by calling its GetEnumerator method directly or by using foreach in C# or For Each in Visual Basic. What is the smallest audience for a communication that has been deemed capable of defamation? Create a class with the desired properties and return a. I tried that and for some reason i was getting an error (invalid expression term 'into'), then i saw you mentioned Navigation Properties, I am fairly new to EF so I started looking into it. This article shows you how to perform four variations of an inner join: A simple inner join that correlates elements from two data sources based on a simple key. The LINQ Except Method in C# is used to return the elements which are present in the first data source but not in the second data source. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. If three leagues are in France, that's three Frances. But filling in your class names is trivial. I have this method that takes a carid and returns one or more drivers for that car. Find centralized, trusted content and collaborate around the technologies you use most. The Join method, which is called by the join clause in C#, implements an inner join. If an element in the first collection has no matching elements, it does not appear in the result set. For example: "Tigers (plural) are a wild animal (singular)", How to create a mesh of objects circling a sphere. Only one row should show, and preferably only one row should be returned from the query. The SelectMany Method in LINQ is used to project each element of a sequence or collection or data source to an IEnumerable<T> type and then flatten the resulting sequences into one sequence.
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