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How to Retrieve Data Using SQL SELECT Statement

Posted by tagicon_admin | in : SQL

Today I will share how to retrieve data by using SQL SELECT statement. Basically SELECT statement are used to identifie  the columns to be displayed. When we want to retrieve or extract data from database table then we use SELECT statement. Now I am showing some example of SQL SELECT statement below:

Syntax of SELECT statement:
====================

SELECT * | {[DISTINCT] column|expression [alias]…..}
FROM table;

–>Example-1: Retrieve all data from employees table by using SELECT statement.

SELECT * 
FROM employees;


EMPLOYEE_ID LAST_NAME      EMAIL           PHONE_NUMBER   HIRE_DATE JOB_ID
----------- -------------- --------------- -------------- --------- -------
        198 OConnell       DOCONNEL        650.507.9833   21-JUN-07 SH_CLERK
        199 Grant          DGRANT          650.507.9844   13-JAN-08 SH_CLERK
        200 Whalen         JWHALEN         515.123.4444   17-SEP-03 AD_ASST
        201 Hartstein      MHARTSTE        515.123.5555   17-FEB-04 MK_MAN
        202 Fay            PFAY            603.123.6666   17-AUG-05 MK_REP
        203 Mavris         SMAVRIS         515.123.7777   07-JUN-02 HR_REP
        204 Baer           HBAER           515.123.8888   07-JUN-02 PR_REP
        205 Higgins        SHIGGINS        515.123.8080   07-JUN-02 AC_MGR
        206 Gietz          WGIETZ          515.123.8181   07-JUN-02 AC_ACCOUNT
        100 King           SKING           515.123.4567   17-JUN-03 AD_PRES

 

–>Example-2: Retrieve last name from employees table by using SELECT statement.

SELECT last_name
FROM employees;

LAST_NAME
-----------
OConnell
Grant
Whalen
Hartstein
Fay
Mavris
Baer
Higgins
Gietz
King

 

–>Example-3: Retrieve first name, employee id, salary  from employees table by using SELECT statement.

SELECT first_name, employee_id, salary
FROM employees;



FIRST_NAME   EMPLOYEE_ID     SALARY
----------   -----------    -------
Donald       	     198       2600
Douglas              199       2600
Jennifer             200       4400
Michael              201      13000
Pat                  202       6000
Susan                203       6500
Hermann              204      10000
Shelley              205      12008
William              206       8300
Steven               100      24000

 

–>Example-4: Retrieve employee id, first name, salary, (salary + 500) *12  from employees table by using SQL SELECT statement.

SELECT employee_id, first_name, salary, (salary+500)*12
FROM employees;

EMPLOYEE_ID FIRST_NAME       SALARY (SALARY+500)*12
----------- ------------- --------- ---------------
        198 Donald             2600           37200
        199 Douglas            2600           37200
        200 Jennifer           4400           58800
        201 Michael           13000          162000
        202 Pat                6000           78000
        203 Susan              6500           84000
        204 Hermann           10000          126000
        205 Shelley           12008          150096
        206 William            8300          105600
        100 Steven            24000          294000

 

–>Example-5: Retrieve department id, department name as deptname from departments table by using SQL SELECT statement.

SELECT department_id, department_name AS deptname
FROM departments;

DEPARTMENT_ID DEPTNAME
------------- -----------------
           10 Administration
           20 Marketing
           30 Purchasing
           40 Human Resources
           50 Shipping
           60 IT
           70 Public Relations
           80 Sales
           90 Executive
          100 Finance

 

–>Example-6: Retrieve first name with add last name from employees table by using SELECT statement

SELECT first_name ||' '||last_name AS "Name"
FROM employees;

Name
------------------
Donald OConnell
Douglas Grant
Jennifer Whalen
Michael Hartstein
Pat Fay
Susan Mavris
Hermann Baer
Shelley Higgins
William Gietz
Steven King
Neena Kochhar
Lex De Haan
Alexander Hunold
Bruce Ernst
David Austin
Valli Pataballa
Diana Lorentz
Nancy Greenberg
Daniel Faviet
John Chen

 

–>Example-7: Retrieve unique department id from employees table by using SQL SELECT statement

SELECT DISTINCT department_id
FROM employees;

DEPARTMENT_ID
-------------
          100
           30

           20
           70
           90
          110
           50
           40
           80
           10
           60

 

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