LINQ retreive values from a table that of which fields(of a cetain column) are not equal of another table

Question

I have two tables which have a column in common , how can I retreive the first table where the values of it's column are not equal to the values of the column of the other table?

Here is an example:

  table1ID | foo    | fooBool        table2ID | foo      | fooin
 ----------------------------        -----------------------------

     1    |  test1  | true              1     |   test2  |    5
     2    |  test2  | true              2     |   test3  |    7
     3    |  test3  | true
     4    |  test4  | false

Therefore the result of the LINQ query for the first table that has values of foo not equal that of table2 are:

table1ID | foo    | fooBool
---------------------------    
   1     | test1  | true
   4     | test4  | false

Answer 1

var results = from t1 in db.table1
              from t2 in db.table2
              where t1.foo != t2.foo
              select t1

Answer 2

You could also use the Intersect() IEnumerable Extension

var results = db.table1.Intersect(db.table2);

Or in LINQ

var codes = from intersected in db.table1.Intersect(db.table2)
            select intersected.foo;

This would produce

 results 
 ----------
 test2
 test3

Update

Thanks to Joe for pointing out that Intersect would produce the common items (added sample above). What you would want is the Except extension method.

var results = db.table1.Except(db.table2);

Or in LINQ

var codes = from diff in db.table1.Except(db.table2)
            select diff.foo;

This would produce

 results 
 ----------
 test1
 test4