**`GROUP BY`** is a SQL command used to merge similar set of data under one field. A user can merge this data according to the field of his/her own choice. A `GROUP BY` returns one record for each group. 

**`COUNT`** is a command which counts the number of records present in a particular field. 

In the illustration below there is a blue circle, some green circles, and a few purple circles; each circle has a particular **hexagon** attached to them. The `GROUP BY` function is called to group the hexagons according to the circles they are attached with. Later, the `COUNT` function is used to count the number of hexagons attached with a particular circle.  

# Example

Suppose there is a table which stores the records of immigrants. It stores their names, IDs and nationality. 

**Table : Immigrants**

|  ID   | Name     | Country    |
| --- | --- | --- |
|  123   | Rooney    |  England   |
|   457  |  Nekham   | Australia     |
|   312 |  George   |   USA  |
|  761   | McKenzie    |  USA   |
|    478 |   McGrath  |   Australia  |
|   567  |  Mukesh   |  India   |
|   978  |  John   |  USA   |
|  445   |   Angelina  | USA    |
|  771   |  Mark   |  Russia   |
|414 |Peter|England|

Now, if this table is **grouped** by nationality and their IDs are to be **counted** and displayed, the code will be :

SELECT COUNT(id), nationality 
  FROM immigrants
 GROUP BY(nationality)

The above code correctly calculates the number of people belonging to each specific country.

How to use SQL COUNT GROUP BY

GROUP BY merges similar data under one field and COUNT calculates the number of records in that field.

ID	Name	Country
123	Rooney	England
457	Nekham	Australia
312	George	USA
761	McKenzie	USA
478	McGrath	Australia
567	Mukesh	India
978	John	USA
445	Angelina	USA
771	Mark	Russia
414	Peter	England