Return the Set Difference Between Two Sequences

Article
2021-09-15

Use the Except operator to return the set difference between two sequences.

Example

This example uses Except to return a sequence of all countries/regions in which Customers live but in which no Employees live.

var infoQuery =
    (from cust in db.Customers
    select cust.Country)
    .Except
        (from emp in db.Employees
        select emp.Country)
;

Dim infoQuery = _
    (From cust In db.Customers _
     Select cust.Country) _
    .Except _
        (From emp In db.Employees _
         Select emp.Country)

In LINQ to SQL, the Except operation is well defined only on sets. The semantics for multisets is undefined.

See also