Some developers say that only changes the order of tables as entity in Linq query, we can get the output as right outer join but this is not true. You can see the following Linq query and the result for this query and above SQL query is not the same.
ProductId equals p. ProductId, o. The resulting records are equal to the product of the number of records in the first table and the number of record in the second table. OrderId, p. View All. Mukesh Kumar Updated date Jul 15, Sometimes, it is required to send data from two or more tables or objects in a single unit based on your provided information.
It includes all rows from the left table and matching rows from the right table. In this join, all the data from right tables come in records as well as matching records with left table.
Actually Linq query is not possible for right outer join. It is nothing but only a Cartesian product of the two or more tables which are participating in join. If you will use the where clause with cross join, it will behave like Inner Join;.
Next Recommended Reading. Net Core 6. Create A. Understanding Thread Starvation in. I have to check the database to find out if an application exists. Personally I don't think 'empty' objects make a whole lot of sense with regard to databases because the existence of an object in a database is a binary condition - i.
That condition is neatly represented in a null-vs-not-null check. Furthermore, the 'Safe Navigation' operator in C 6. Show 3 more comments. Active Oldest Votes. I would argue that your code is going to far in canonicalization of the result. Improve this answer. Erik Eidt Erik Eidt This is a nice solution.
Do you know if that's going to issue two separate queries to the database though? I'm betting it will. Hitting the database twice may be undesirable. RubberDuck: That can be solved by a simple. ToList after the where, before the any. Add a comment. It depends! There are different options depending on what you want to achieve: Return null if the item is not found. The only thing you should not do: return an "empty" instance of the class. JacquesB JacquesB An "empty" instance does make sense in many cases e.
Boolean blindness argues against approaches via booleans. As you state, I would throw an exception if not getting a result should "never happen", otherwise I would use the Option approach. Since nulls are, unfortunately, already ubiquitous in C , I may use null in a temporary, localized way. I like retuning null when something is not found. To me it makes sense. That way you can do a for each on the list and it naturally does nothing if nothing is found. Ewan Ewan Could you clarify what you mean by: "move your mapping to after the select!
Some code would help. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. I checked System. Will the same thing work? Yeah and I tried this and close enough didn't cut it. After I removed the case statement, the sql came back fine You don't have to modify your dbml.
You can just cast xx. Online to a nullable int. AnIntegerValue ; The second one will return 0 when no rows match the where clause. Slaggg Slaggg 6, 7 7 gold badges 26 26 silver badges 27 27 bronze badges.
Looks like the type is boolean and therefore can never be null and should be false by default. Ray Booysen Ray Booysen How can you make it false by default if its from a join? It will be false by default surely? It is a boolean and has not been set, so it should be false. What are you seeing? Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Stack Gives Back
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