Question: I have customer some customer records in which one of the fields is country. 

Say below are the records and column A is customer number, column be is customer name and column C is country

```
CNumber  CName     CCountry
-----------------------------
0001     CustomerA USA
0002     CustomerB Japan
0003     CustomerC France
0004     CustomerD Hoss

```

In the SQL server database, there is already a tabled name COUNTRY which has all the countries there is listed there. What would be the query to compare that all the customers have a valid country name in column C. Like we can see customer 0004 has the country Hoss which is not a country. I need the query to tell me its an invalid country for the 0004 customer.

Thanks for any help.

Answer: 
try `Array.slice()` method:

```
getThingsById(ID: number): Observable<IThing[]> {
  return this._http.get(`${this.URL}${ID}/things`)
    .map((response: Response) => <IThing[]>response.json().slice(0, 20));
}

```
Observables don't appear to work as described when using it with Http. With Http there is **ONE** response that comes back from the server. That ONE response has the entire set of requested data.

So the Observable contains the entire set of requested data from the ONE response.