A **query in SQL** is used to retrieve, insert, or update the data in a table. A *subquery* is a query within a query. 
 

# Clauses of a subquery
There are **three** clauses of any subquery: 
* A **`SELECT` clause**: specifies the field to be extracted from the specified table.

* A **`FROM` clause**: specifies the table from where the data is retrieved.
* A **`WHERE` clause**: specifies the condition on which the retrieval is based.

## Sample table of "employees"


|  emp_id   |first_name     |  last_name   | quality  
| --- | --- | --- | --- |--- |
|  1   |  George   | Cleverly     | Speaks well    
|  2   |   Tom  | Rooney    | Manages well   
|  3   | Jazz    |  Cleverly   |     Punctual
|   4  | Clarke    |   James  | Quick worker    
|    5 |   Wash  |  Ramp   |Manages well    
|    6 |  Hill   |   Billings  |  Quick worker   

## Sample table of "ratings"

|   emp_id  |  rating   |
| --- | --- |
|   1  |  3   |
|  2   |  1   |
|   3 |    2 |
|    4 |    5 |
|     5|   2  |
|     6|    4 |

​### Code
The following example uses all three clauses to display the employees who have a rating higher than 3. 

SELECT a.emp_id, a.first_name, a.last_name, b.rating
FROM Employee a, ratings b
WHERE a.emp_id = b.emp_id AND b.rating > 
(SELECT rating
FROM ratings
WHERE rating=3);

What is an SQL subquery?

A query in SQL is used to retrieve, insert, or update the data in a table. A subquery is a query within a query. 

What is an SQL subquery?

Clauses of a subquery

Sample table of “employees”

Sample table of “ratings”

emp_id	first_name	last_name	quality
1	George	Cleverly	Speaks well
2	Tom	Rooney	Manages well
3	Jazz	Cleverly	Punctual
4	Clarke	James	Quick worker
5	Wash	Ramp	Manages well
6	Hill	Billings	Quick worker