Question: Let's say you have parameters(s) in your LINQ query where clause, how do you handle that?

Here is an example:

```
var peoples= from i in individuals
  where (string.IsNullOrEmpty(lastName) i.LastName.Equals(lastName))
  select i;

```

Answer: 
Try to understand what's going on under the hood:

* How query expressions are translated by the compiler
* How LINQ to Objects streams its data, and how it defers execution
* How queries execute remotely via IQueryable and expression trees

It's also worth becoming comfortable with both query expressions, e.g.

```
var query = from person in people
            where person.IsAdult
            select person.Name;

```

and "dot notation":

```
var query = people.Where(person => person.IsAdult)
                  .Select(person => person.Name);

```

Knowing both will let you choose the most readable form for any particular query.
[101 LinQ Samples](http://msdn.microsoft.com/en-us/vcsharp/aa336746.aspx) you can start with samples from MSDN