Linq Expression Join

LINQ to SQL Left Outer Join. Counts number of items in the IEnumerable collection. The difference between a Right Anti-Semi-Join is mostly moot with Linq to Objects or in the source, but makes a difference on the server (SQL) side in the final answer, removing an unnecessary JOIN. NET classes. Product_Id into grpOrdersjoin Products. There was one particular ASP. Sum (LINQ) Enumerable. In LINQ, Lambda expression is a function without a name. It is the same as inner join of SQL. It returns sum of numeric values in collection. The Join extension method has two overloads as shown below. 5 is to consize the concept of Annonymous function writing. Expression in LINQ. Code that operates within the. LINQ Query for inner join with multiple table: Below LINQ query will get data from multiple tables by using inner join. var UserInRole = db. Language Integrated Query (LINQ) is the collection of standard query operators that adds query facilities into. It is used to express the following logic: For each item p in the collection, order by property (publication year, in this example). It returns sum of numeric values in collection. LINQ is powered by a framework LINQ to Objects the Enumerable extension. This lets us compose query at runtime. This project contains about 101 samples using LINQ. InvalidOperationException: The LINQ expression '(s) => IsDefined(s. The JOINs that will be covered include INNER JOIN (two and multiple tables), OUTER JOIN (left, right, and full), and CROSS JOIN. Net MVC 3 for the user UI, and a C# class library fo. Learn how to use LINQ in your applications with these code samples, covering the entire range of LINQ functionality and demonstrating LINQ with SQL, DataSets, and XML. Orderby(x=>x. Build left outer join with multiple conditions using Dynamic Linq I am trying to build Dynamic Left outer joinLinq query. Matt Warren's series of articles on IQueryable providers includes an ExpressionVisitor implementation that makes it easy to rewrite expression trees. Unfortunately though it doesn't work in. parser -parse tree -Linq expression tree conversion that's the trouble: the linq expression tree has to refer to elements in the code, or at least has to be able to. Code that operates within the. Let’s assume parameters with the name simpleParam (string) and manyParam (ICollection). This allows us to call the expensive calculations once per iteration. Sum for Numeric Types. The expression trees are handed over to LINQ Providers, which are data source-specific implementations that adapt the LINQ queries to be used with the data source. Edit: I was not clear enough, I'm talking about the Dynamic LINQ library, not native SQL:. Learn how to use LINQ in your applications with these code samples, covering the entire range of LINQ functionality and demonstrating LINQ with SQL, DataSets, and XML. Net framework 3. The value that is returned by the statement depends on the operator used. The translation for: from a in AA join b in BB on a. Join support from MongoDb. OrderLines where Orders. These methods perform equijoins or joins that match two data sources based on equality of their keys. Into Into keyword allows creating a temporary variable to store the results of a group, join or select clause into a new variable. Name,sum(OrderLines. When re-linq is used to convert to a query language that does not support where clauses before join clauses, it can just reverse the order – semantically these arrangements should be equivalent. Any way to dynamically choose fields in a LINQ query expression? It would have been a trivial join if q_Category had in columns what it actually holds in rows. Reference that in your project. If you want to include the orders regardless of whether it has any detail lines, you would need to turn this inner join into an outer join using the DefaultIfEmpty extension method. It returns sum of numeric values in collection. it is a boolean comparisons with anonymous type. The following code relies on the LinkKit Project that allows you to pass expressions and invoke them to your query. The way LINQ is constructed that methods like JOIN, WHERE, SELECT, GROUPBY, have all their own little lambda parameters. You simply loop over each element in your array and add it to the dictionary if it isn't already there. This object describes a tree of members, operators, calls, conditions… that can be, during runtime, either read/parsed or compiled into a delegate. ) to create expression tree nodes of specific types. LINQ is a cool feature in C# 3. Input tables. Type)' could not be translated. After some initial hesitation, I have. Lambda Expressions are confusing when we first walk up to them. We can assign the result of manipulation to temporary variable inside query and we can use that temporary variable to another manipulation. EtaId where e. For LINQ to Entities, apparently these methods enable fluent method chaining, implement the same LINQ query expression pattern as LINQ to Objects and Parallel LINQ. Table Gets the 'CourseSelection' entities from the SQL connection. Hi, I am trying out relatively new feature "Linq To AX" allowing using Linq queries with AX table proxies. Sometimes when you're making a windows phone 7 rest client you just want to look at some of the returned data to poke see what's there. ArrivalDecRecieved == null && e. LINQ interfaces with C# and Visual Basic. For a JOIN or INNER JOIN or CROSS JOIN, there is no difference between a constraint expression in the WHERE clause and one in the ON clause. I've posted about XLinq and using linq to sort and filter lists. LINQ Query for inner join with multiple table: Below LINQ query will get data from multiple tables by using inner join. Not having a header can save a bit of typing with ad-hoc scripts. Goals of LinQ. Download Presentation LINQ - 2 An Image/Link below is provided (as is) to download presentation. As you know, Inner join returns only those records or Understanding Expression and. In this tutorial let us look into how to use Join Query in Entity Framework to load the data from two or more tables. Currently I'm starting a new system on my company, and we are using a good separation between models, views and controllers, basically using Asp. Count Examples. BookTypes from B in MyEntity. The anonymous type initializer expression infers both type and name of members from the expression you supply. For these parameters, you can pass in a lambda expression and it will be compiled to an Expression. Unfortunately LINQ queries are often written as a direct translation of a SQL query, without taking advantage of the richer features offered by LINQ to SQL and LINQ to Entities. Note that there's no explicit operator for the cross join. Alright, so the LINQ query select all client that start with the letter A to filter a little bit the amount of returning data and then join to this result all orders. As building blocks of LINQ query expressions, these operators offer a range of query capabilities like filtering, sorting, projection, aggregation, etc. The only difference between ordinary joins (inner joins) and left joins in LINQ is the use of "join into" and "DefaultIfEmpty()" expressions. 5 is to consize the concept of Annonymous function writing. Let keyword provides facility to declare a temporary variable inside the Linq Query. I’m thinking to write an update of this article and add Query Expressions (syntactic sugar) in Roslyn. ALL Online Courses 75% off for the ENTIRE Month of October - Use Code LEARN75. FirstOrDefault(); You must understand your linq statement. It returns a new collection that contains elements from both the collections which satisfies specified expression. NHibernate's advantage is that it supports persistence ignorance, something that LINQ to Entities won't support. t) Note the introduction of "z" here - basically that contains both t and l from the original expression. Here I have collected various examples for each operator in LINQ and the equivalent Lambda Expressions. For example, in a bank, the manager has two lists, the first list contains the personal details and another list contains the home loan details. A Left outer join is a join in which each element of the first collection is returned, regardless of whether it has any correlated elements in the second collection. How do you for example allow a query to use a dynamic field in a query and then query its data?. I have been using LINQ for a while now for pretty standard queryies, usually against object collections. Max(); // maxNumber: 3. Notice in particular lines 5 and 6, which form the heart of the query. They are a convenient way to represent the delegate passed to LINQ queries like System. Let’s assume parameters with the name simpleParam (string) and manyParam (ICollection). The GroupJoin operator performs the same task as Join operator except that GroupJoin returns a result in group based on specified group key. Foreign keys? What are those? Alas, I digress… At first glance, LINQ appears. OrderLinesgroup Orders by Orders. These joins can’t do with query expression, because doesn’t exit in LinQ (syntactic sugar). All the LINQ code in this article is in C# language. Linq is always associated with Lambda Expressions. Expression Tree ZEfficient in-memory data representations of lambda expressions ZChanging the behaviors of the expressions ZApplying your own optimization Methods Extension You can control not only by Lambda Expression, but also by methods extension LINQ Operations Join ZWhen there is relationship (e. LINQ simplifies creating and executing query expressions. Expression in LINQ. Net, C#, Expression, Lambda, Linq, Select, SQL, Where. Join a community of over 2. Books where BT. LINQ expressions can also be used to write more complex queries to a look up table. EtaId where e. In this post, we will see an example of how to do a Left Outer Join in LINQ and C#. Learn LINQ in easy steps starting from LINQ API, LINQ query syntax & method syntax, Lambda expression, standard query operators and expression tree. Integrate data queries into. This means that it filters resultant items (CityExtended). 15) Explain what are LINQ query expressions? Query expression is nothing but an LINQ query. A LEFT OUTER JOIN is one of the JOIN operations that allows you to specify a join clause. A so-called outer join can be expressed with a group join. Below are the first seven parts in this series:. Efficient querying with LINQ, AutoMapper and Future queries 11 March, 2014. Id where OrderLines. Where(p => p. It is not uncommon to see code doing a join manually. A Left outer join is a join in which each element of the first collection is returned, regardless of whether it has any correlated elements in the second collection. Enumerable type, most of which are IEnumerable extension methods. LINQ to SQL is a built-in O/RM (object relational mapper) that ships in the. Today, in this article let's play around with one of the interesting and most useful concepts in LINQ. Both LINQ to SQL and LINQ to Entities are _years_ behind other ORM's, including NHibernate. It contains information for sorting, filtering, grouping or joining to apply to the source data. Lambda expression is a concept coming from functionnal programming, and that provides shorthand for specifying an algorithm. ) to create expression tree nodes of specific types. than Expression Trees (the. Basically I need to use LINQ join as a lambda expression. With the merging helper method we can reuse the query for the basic list and just extend it with the added properties. The IEnumerable interface is central to LINQ. This article describes the use of the SelectMany operator, which allows one-to-many object hierarchies to be flattened and queried. Product_Id,Products. For LINQ to Entities, apparently these methods enable fluent method chaining, implement the same LINQ query expression pattern as LINQ to Objects and Parallel LINQ. One common complaint over the years is people using ORMs use the tool identically for both reads and writes. To access standard LINQ query operators, the namespace System. Language Integrated Query (LINQ) is the collection of standard query operators that adds query facilities into. So what do I mean by "Hacking LINQ Expressions"?. This took me 61 ms. Lambda Expression of. In a SQL SELECT statement, the second set of data can be specified in a NATURAL JOIN clause, and the equalities used to join the tables are implicit. LINQ was designed to address the issues illustrated by the example above. Figure 03: The complex expression tree generated by the simple LINQ to SQL query expression shown above. Net) that extends these languages with query operators and some other features that make it possible to integrate queries in the languages. Expressions v4. I need to join all the below tables and based on clientsID in Productsclients table I need to. A LEFT OUTER JOIN is one of the JOIN operations that allows you to specify a join clause. Let’s assume parameters with the name simpleParam (string) and manyParam (ICollection). Data; using System. Join support from MongoDb. Today, in this article let's play around with one of the interesting and most useful concepts in LINQ. How do you for example allow a query to use a dynamic field in a query and then query its data?. Any way to dynamically choose fields in a LINQ query expression? It would have been a trivial join if q_Category had in columns what it actually holds in rows. Query Expression Syntax Examples: Join Operators (LINQ to DataSet) 03/30/2017; 4 minutes to read +7; In this article. 7 thoughts on “ Executing LINQ Queries in PowerShell - Part 2 ” js May 29, 2018 at 2:37 pm. What is Query Operator in LINQ ? There are some query-patterns which define how we should write query on data using LINQ; those patterns are designed with the help of extension methods, those query patterns are known as Query Operators Based on functionalities LINQ query operators can be categorized into the following ways. Join Olivia Chiu Stone for an in-depth discussion in this video, Join queries with lambda expressions, part of LINQ with C# Essential Training. ArrivalDecRecieved == null select e). The relational operators like Select, Project, Join, Group, Partition, Set operations etc. The types in the System. For instance, suppose we want to list all purchases of $1000 or greater made by customers who live in Washington. ArrivalDecRecieved == null && e. Whilst the accepted answer works and is good for Linq to Objects it bugged me that the SQL query isn't just a straight Left Outer Join. Join Olivia Chiu Stone for an in-depth discussion in this video Group queries with lambda expressions, part of LINQ with C# Essential Training Lynda. Give me the option to match. A Left outer join is a join in which each element of the first collection is returned, regardless of whether it has any correlated elements in the second collection. Type inference failed in the call to GroupJoin (LINQ to XML) 10:23 PM C# , LINQ , XML No comments Hi,. LINQ only supports equality joins, there's not a way to use a different operator in the join itself. 5, they were strictly for expressions, but the Dynamic Language Runtime uses expression trees to represent operations, and the range of logic represented had to expand accordingly, to include things like. It's built so much it's almost a developer's rite of passage. It has an good explanation on Linq inner workings and the accepted answer has a method that do the outer join. net, data-access-layer, linq-to-entities, linq-to-sql, orm Accessing System Databases/Tables using LINQ to SQL? Right now I have an SSIS package that runs every morning and gives me a report on the number of packages that failed or succeeded from the day before. Using SelectMany, this LINQ (Lambda Expression) sample in C# cross joins two arrays, and gets cartesian product. The LEFT JOIN returns all records from the left table (table1), and the matched records from the right table (table2). Usually this is not visible to the user. LINQ | Join (Inner Join) In LINQ, Join operators are used for integrating two data source into one data source which shares some common attributes. It is always advisable to use navigational properties to query the related data. For these parameters, you can pass in a lambda expression and it will be compiled to an Expression. Product_Id,Products. Sum (LINQ) Enumerable. Gets sum of values from list of integer numbers. It's not generating raw SQL, EF will interpret it and generate an expression but the syntax is SQL-like. Check following linq self join example. GroupBy-s premise is to group items by a key and since keys in dictionaries are required to be unique, using this method to find duplicate items makes sense. In case, If no matching elements found from right collection with left collection then the join clause will return an empty array. JOINS in LINQ. This release of the Toolkit has a lot of goodies including a new TreeMap control, a Rating control (written by yours truly), and a useful collection of extensions methods for TreeView. UserProfiles. Etas join a in db. Putting each LINQ operator on a new line, translating the "unspeakable" identifiers to ones we can "speak", changing the anonymous types to their familiar form and changing the AndAlso expression-tree lingo to && exposes the transformations the compiler does to arrive at an equivalent in dot-syntax:. It can help us convert SQL logic to C# code in some cases as well. I personally don’t have a favorite between Linq and fluent, however, I find it easier to get my teammembers to write Linq (as they have an intense SQL background). So let's discuss some daily use ordering of records with. Thus, I find it would be much easier to understand your filter class if you renamed the ExerciseFilter to ExerciseId and replaced both properties with CanApplyExerciseFilter and CanApplyDateFilter. I prefer the "LINQ syntax" for Joins as I think it looks cleaner. There was one particular ASP. In LinQ To SQL, Right Join Operation can be achieved in the similar way as left join that we just did, just by changing the table name in the last part:. It returns a new collection that contains elements from both the collections which satisfies specified expression. 5 release, and which enables you to model relational databases using. Syntax of LINQ Left Outer Join Following is the syntax of using LINQ Left Join to get all the elements from left collection and matching elements from right collection. GroupJoin is an extension method. Using LINQ there are two issues that I've been struggling with and both have to do with dynamic query results: Hitting the wall with SQL that can't be expressed via LINQ and using dynamic expressions inside of LINQ queries from within framework level code. Query Expression Syntax Examples: Join Operators (LINQ to DataSet) 03/30/2017; 4 minutes to read +7; In this article. Product_Id = Products. One common complaint over the years is people using ORMs use the tool identically for both reads and writes. Using AutoMapper to perform LINQ aggregations 8 April, 2014. I need to join all the below tables and based on clientsID in Productsclients table I need to. The below post describes how you can use a Dynamic Query Library provided by the LINQ team to dynamically construct LINQ queries. The GroupBy query operator and the group clause both allow grouping using a single key selector. LINQ uses an SQL-like syntax to make query expressions well beyond the capabilities of embedded SQL, as implemented in programming languages. It is always advisable to use navigational properties to query the related data. Idea behind LINQ LINQ (Language Integrated Query) was introduced in. If you want a right outer join, you need to flip the logic of your query to turn it into a left outer join. Lambdas & LINQ in C# - Part 1: Lambda Expression. It is the same as inner join of SQL. That means that you can call any LINQ method on any object that implements IEnumerable. NET, Entity Framework, LINQ to SQL, NHibernate / Nested Select in LINQ using Lambda expression Nested Select in LINQ using Lambda expression RSS 3 replies. The Join extension method has two overloads as shown below. Download the Free Version of LINQPad. LINQLINQ is po ered b lang age LINQ is powered by language enhancements Some of which we have already seen (C# 3. 'je vous propose une class permettant de faire un left join entre deux datatable 'j'ai trouvé une solution qui fonctionne mais il y a surement mieux 'Je poste ici ce code car il y a beaucoup de recherche sur google pour ce genre de chose. It groups one collection of objects by a key and joins those groups with another collection of keyed objects. It is always advisable to use navigational properties to query the related data. If you want a right outer join, you need to flip the logic of your query to turn it into a left outer join. Using Join, this LINQ (Lambda Expression) sample in C# joins two arrays where elements match in both. To access standard LINQ query operators, the namespace System. You could do this with a LINQ to SQL query expression, or call a Stored Procedure or use a Custom SQL Expression to retrieve the LINQ to SQL data model. A from expression (also referred to as a LINQ expression, short for "Language INtegrated Query") always starts with the keyword from, and its result is a new Sequence of the same or a derived (and possibly anonymous) type. The data for the detail view is held in a CarExtendedInfo class which is derived from the CarBasicInfo class. com courses again, please join LinkedIn Learning. linq_expression_with_error_handling. It is a LEFT join query, starting with the first (left-most) collection (TravelItems) and then matching second (right-most) collection (CityExtended). Query should be imported by default. BookTypeId == B. The join methods provided in the LINQ framework are Join and GroupJoin. In case, If no matching elements found from right collection with left collection then the join clause will return an empty array. Its methods and query expressions often improve the readability of programs. com | Email:info at java2s. Our LINQ tutorial is designed for beginners and professionals. BookTypeId select new { BookTypes = BT, Books = B. The Join operator operates on two collections, inner collection & outer collection. LINQ lacks non-equijoins, cross joins, and other options; however, the insertion of multiple from clauses achieves the same function. Note that there's no explicit operator for the cross join. Generic; using System. Doesn’t LINQ require me to specify the criteria at compile time in order to construct the query? Fortunately the answer’s no, LINQ supports constructing dynamic queries at runtime through the Expression Tree API and the Expression Compiler. LINQPad is a FREE tool that can execute any C#/VB/F# expression, statement block or program with rich output formatting. Joining two generic lists in linq is tricky, in this article we will see how we can join two lists by using inner join and then by using outer join. js (jQuery plugin) support Windows Script Host binding for Reactive Extensions for JavaScript(RxJS) and IntelliSense Generator -> see documentation. Stack trace: "System. It returns a new collection that contains elements from both the collections which satisfies specified expression. Syntax of LINQ Left Outer Join Following is the syntax of using LINQ Left Join to get all the elements from left collection and matching elements from right collection. Here is an example on joining two tables using lambda expression. This object describes a tree of members, operators, calls, conditions… that can be, during runtime, either read/parsed or compiled into a delegate. var UserInRole = db. In a LEFT JOIN, the extra NULL row for the right-hand table is added after ON clause processing but before WHERE clause. Downloading the LINQ Dynamic Query Library Included on the VS 2008 Samples download page are pointers to VB and C# sample packages that include a cool dynamic query LINQ helper library. T4 templates to generate data models for LINQ to DB SQL. LINQ also represents the set of method names with the translation rules that can be used by the compiler for converting fluent-style query expressions into expressions that uses these method names, anonymous types and lambda expressions. Compile is an inbuilt method in the Expression class. How do you for example allow a query to use a dynamic field in a query and then query its data?. The Join operator operates on two collections, inner collection & outer collection. Calling functions in LINQ queries The LINQ project (see [ 1 ]) is an extension to. Joining is an important operation in queries that target data sources that have no navigable relationships to each other, such as relational database tables. The hand coding of Expression to handle merging an Expression> into a lambda could be improved with LinqKit, but it would be nice if the. The lambda expression in visual basic Function(y) y * y. In linq, Group join produces a sequence of object elements based on the matching elements from both left and right collections. ) Rather, those operators return a query (essentially an IEnumerable ). LINQ to Entities is a simple and easy way to query the entities using C#. LINQ to SQL Left Outer Join. Many LINQ methods take a function (called a delegate) as a parameter. Language Integrated Query (LINQ) is the collection of standard query operators that adds query facilities into. You also will see some code for LINQ to SQL that is pretty straightforward and my last article, "Search and Replace with Regular Expressions," and my upcoming book, LINQ Unleashed: for C#, cover LINQ to SQL in detail. In LINQ, a Join clause with an into expression is called as a Group join. ServiceTypes. Sometimes when you're making a windows phone 7 rest client you just want to look at some of the returned data to poke see what's there. Product_Id =270 group by OrderLines. In line 6, for instance, we can see that the join is formed on the ProductId field shared by each table. Ravi Kumar C++/C# Team. var UserInRole = db. ArrivalDecRecieved == null select e). Following that example I will show one how to use the same Linq entity to put that CSV data into a dictionary, a hash table, where the key of entry is the first column’s data. ) Rather, those operators return a query (essentially an IEnumerable ). Which options does OpenAccess and LINQ provide to perform string matching? Into which SQL is the LINQ expression translated? Let’s use a simple class model for this post: a Person with a FirstName, a LastName and a NickName. This post also can serve as a base for further extension of the Dynamic Linq Library and adding support to more extension methods. A LEFT OUTER JOIN is one of the JOIN operations that allows you to specify a join clause. It seems a tad over complicated and I'm pretty sure LINQ has something to offer that makes my life much easier. Expression Trees, Take Two – Introducing System. The lambda expression has the following basic form. When you perform the above linq statement, you could debug your code and check the. Previously, we looked at demystifying LINQ method syntax, including Where, OrderBy, and SingleOrDefault. Linq namespace. It marries a C# Regular Expression MatchCollection to a property list using Linq. NET can be downloaded over here (Github). On the other hand, if the only statement in the lambda expression is the return statement, then the second, abbreviated form can be used. Currently I'm starting a new system on my company, and we are using a good separation between models, views and controllers, basically using Asp. GroupJoin requires same parameters as Join. You can use LINQ to perform a left outer join by calling the DefaultIfEmpty method on the results of a group join. In linq, Group join produces a sequence of object elements based on the matching elements from both left and right collections. Query should be imported by default. Linq is better for these kind of operations as it resembles SQL. The first is that we create new Sales objects, and Contains is a reference operation. The part of the syntax in the parentheses after the operator is called the "lambda expression. Hi, I am trying out relatively new feature "Linq To AX" allowing using Linq queries with AX table proxies. Hacking LINQ Expressions: Join With Comparer 19 September, 2009. Expressions namespace. Language Integrated Query ( LINQ ) is a component in. Converting ODataQueryOptions into LINQ Expressions in C# 2017-03-01 by Ronald Rink 24 Comments OData makes it very easy for us to pass query options from the URL down to an object mapper like EntityFramework. Func when the Enumerable. I am an experienced senior developer / technical architect with over 8 years experience working with digital agencies in London, and full application lifecycle experience. NET, and enables you to efficiently express queries in your programming language of choice. When working with LINQ to SQL, foreign key tables are represented in the object model as properties of the primary table. In this article, I will demonstrate the group join because that's how you get to a left join. All the LINQ code in this article is in C# language. Here goes the query for grabbing employee name, salary and department name by joining above said three table using lambda. We can proceed as follows:. js (jQuery plugin) support Windows Script Host binding for Reactive Extensions for JavaScript(RxJS) and IntelliSense Generator -> see documentation. Expressions define expressions in an easier-to-process manner. Goals of LinQ Anatomy of a LinQ query More expression examples LinQ to Objects LinQ to XML LinQ to SQL. And they sometimes lead to new, delayed, superior algorithms. Expressions are the assemblies you all need. The type of one of the expression in the join clause is incorrect. In LINQ, explicit join clauses are only required when two source sequences are not tied by any relationship. Note that there's no explicit operator for the cross join. Most of the developers are struggling for the syntax and examples. Using the LINQ extensions in the C# language, we can implement join expressions. The GroupJoin operator performs the same task as Join operator except that GroupJoin returns a result in group based on specified group key. In Visual Studio 2008, any valid VB expression can be represented as an expression tree. Whilst the accepted answer works and is good for Linq to Objects it bugged me that the SQL query isn't just a straight Left Outer Join. 5, which support the LINQ syntax makes it possible to work with a configured data store without resorting to ADO. Gets sum of values from list of integer numbers. What I am trying to achieve is to write the same query that starts on line 23 with lambda expression syntax on line 30. PubDate is used with respect to the OrderBy method. from p in Posts join pm in Post_metas on p. Foreign keys? What are those? Alas, I digress… At first glance, LINQ appears. If they choose so, the LINQ Providers analyze the expression trees contained in a query in order to generate essential pieces needed for the execution of a query. Join Olivia Chiu Stone for an in-depth discussion in this video Group queries with lambda expressions, part of LINQ with C# Essential Training Lynda. LINQ simplifies creating and executing query expressions. Since I would really like people to pitch in and help with the implementation of Linq for NHibernate (not that this is a hint or anything), I decided to document what I found out while building Linq for NHibernate.