Can we do left join in LINQ?
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. You can use LINQ to perform a left outer join by calling the DefaultIfEmpty method on the results of a group join.
Is left and left outer join same?
There really is no difference between a LEFT JOIN and a LEFT OUTER JOIN. Both versions of the syntax will produce the exact same result in PL/SQL. Some people do recommend including outer in a LEFT JOIN clause so it’s clear that you’re creating an outer join, but that’s entirely optional.
What is left outer join in SQL?
A left outer join is a method of combining tables. The result includes unmatched rows from only the table that is specified before the LEFT OUTER JOIN clause. If you are joining two tables and want the result set to include unmatched rows from only one table, use a LEFT OUTER JOIN clause or a RIGHT OUTER JOIN clause.
What does a left outer join give you?
Left Outer Join returns all the rows from the table on the left and columns of the table on the right is null padded. Left Outer Join retrieves all the rows from both the tables that satisfy the join condition along with the unmatched rows of the left table.
What is DefaultIfEmpty in Linq?
The DefaultIfEmpty operator is used to replace an empty collection or sequence with a default valued singleton collection or sequence. Or in other words, it returns a collection or sequence with default values if the source is empty, otherwise return the source.
What is group join in Linq?
In simple words, we can say that Linq Group Join is used to group the result sets based on a common key. So, the Group Join is basically used to produces hierarchical data structures. Each item from the first data source is paired with a set of correlated items from the second data source.
IS LEFT join THE SAME AS join?
The LEFT JOIN statement is similar to the JOIN statement. The main difference is that a LEFT JOIN statement includes all rows of the entity or table referenced on the left side of the statement.
How does outer join work in SQL?
In an outer join, unmatched rows in one or both tables can be returned….Outer joins
- LEFT JOIN returns only unmatched rows from the left table.
- RIGHT JOIN returns only unmatched rows from the right table.
- FULL OUTER JOIN returns unmatched rows from both tables.
Can FirstOrDefault return null?
The major difference between First and FirstOrDefault is that First() will throw an exception if there is no result data for the supplied criteria whereas FirstOrDefault() returns a default value (null) if there is no result data.
What is FirstOrDefault C#?
FirstOrDefault() Returns first element of a sequence, or a default value if no element is found. It throws an error Only if the source is null. you should use it, If more than one element is expected and you want only first element.
Can we use group by with join in SQL?
SQL Inner Join permits us to use Group by clause along with aggregate functions to group the result set by one or more columns. Group by works conventionally with Inner Join on the final result returned after joining two or more tables.