SELECT

MySQL

Example

SELECT firstName, lastName
FROM Employees
WHERE department = 'Sales';

Output

firstName	lastName
John	Doe
Jane	Smith

Explanation

The SELECT statement retrieves data from the ‘Employees’ table. Only employees whose department is ‘Sales’ are included, and only their First and Last names are displayed.

PostgreSQL

Example

SELECT name, age FROM Users WHERE age > 30;

Output

 name  | age
-------|-----
 John  | 32
 Alice | 35
 Bob   | 45

Explanation

The provided SQL command selects and displays the ‘name’ and ‘age’ of users from the ‘Users’ table where the ‘age’ is greater than 30.

SQL Server

Example

Here is the simple SQL query:

SELECT *
FROM Employees;

Output

Assume that a table named Employees contains the following data:

| EmployeeID | FirstName | LastName |
|------------|-----------|----------|
|     1      |    John   |   Doe    |
|     2      |    Jane   |   Doe    |
|     3      |    Bob    |  Smith   |

Explanation

The SELECT statement is used to select data from a database. The data returned is stored in a result table, called the result-set. It is the most commonly used statement in SQL. ”*” is used to select all columns present in a table. Here, SELECT * FROM Employees; retrieves all data from the ‘Employees’ table.

Oracle

Example

SELECT first_name, last_name
FROM employees
WHERE employee_id = 100;

Output

FIRST_NAME  | LAST_NAME
--------------------
Steven      | King

Explanation

In the example, the SELECT statement is used to retrieve specific data from a database, which in this case is the first_name and last_name columns from the employees table. The WHERE clause is used to filter the records and only include employees whose employee_id is 100. Therefore, the output reflects the first name and last name of the employee with the ID of 100.

SQLite

Example

CREATE TABLE employees (
    id INTEGER PRIMARY KEY,
    name TEXT,
    position TEXT,
    salary INTEGER
);

INSERT INTO employees (name, position, salary)
VALUES ('John Doe', 'Manager', 5000),
       ('Jane Smith', 'Sales Associate', 3000),
       ('Alice Johnson', 'Accountant', 4000);

SELECT * FROM employees;

Output

id  | name           | position        | salary
----|----------------|-----------------|------
1   | John Doe       | Manager         | 5000
2   | Jane Smith     | Sales Associate | 3000
3   | Alice Johnson  | Accountant      | 4000

Explanation

The SELECT * FROM employees; command is used to query all records from the employees table. It returned a table with all employees with their respective id, name, position, and salary. The command SELECT * is used to select all columns from the specified table.