I want to merge the records of two IQueryable lists in C#. I try 

```
IQueryable<MediaType> list1 = values;
IQueryable<MediaType> list2 = values1;
obj.Concat(obj1);

```

and 

```
IQueryable<MediaType> list1 = values;
IQueryable<MediaType> list2 = values1;
obj.Union(obj1);

```

but if `list1` is empty then the resultant list is also empty. In my case either `list1` can be empty but `list2` can have records. How should i merge them?