Basic SELECT Statement

Description :

 A SELECT statement retrieves information from the database.

Syntax:

 

SELECT *|{[DISTINCT] column|expression [alias],...}

 FROM    table;

    SELECT                   :  is a list of one or more columns.

  *                             : selects all columns.

  DISTINCT                : suppresses duplicates.

  column|expression : selects the named column or the  expression.

  alias                       : gives the selected columns different headings.

  FROM table            : specifies the table containing the columns.

Examples:

SELECT *

FROM   departments;

The select statement display all the columns and all rows of the DEPARTMENTS table.

The department table contains four columns: DEPARTMENT_ID,DEPARTMENT_NAME,MANAGER_ID, and LOCATION_ID.

The table contains eight rows, one for each department. 

SELECT department_id, location_id

FROM   departments;

You can use the SELECT statement to display specific columns of the table by specifying the column names, separated by commas. 

The select statement display all the department numbers and location numbers from the DEPARTMENTS table.

 

SELECT last_name as "Name" , salary*12 "Annual Salary"

FROM   employees;

Using Column Alias.

SELECT DISTINCT department_id

FROM   employees;

Using DISTINCT.