Oracle SQL Tutorials – Chapter 1 (Part 3 of 3)

ARITHMETIC OPERATORS

  • Arithmetic operations can be used on the data which type is ‘date’ or ‘number’.
  • The priority of the operators is like below ;

 

USAGE OF THE ARITMETHIC OPERATORS

  • Let’s list the name, surname, salary and the new salary which is increased by 5% ; and give alias to them.

SELECT first_name NAME, last_name SURNAME , salary SALARY,(salary+salary*8/100)as NEW_SALARY FROM hr.employees;

 

THE NULL VALUE

  • Null is a value that is unknown, unspecified or inconvenient.
  • Null value is not zero(0) or whitespace. It is a common mistake.
  • If a null value joins an arithmetic operation the result will be null.

 

  • Let’s list the name, surname, salary, and commission if it exist, with the aliases.

SELECT first_name NAME, last_name SURNAME , salary SALARY, (salary*commission_pct)as COMMISSION FROM hr.employees;

 

THE CONCATENATION OPERATOR

  • It combines columns or character sets with other columns.
  • It is represented as double pipe : ||
  • It creates a columns which is character type.
  • Also , CONCAT command can used to concetanation.

 

  • Let’s list the name, surname and salary with concatenation.

SELECT first_name||’ ‘||last_name AS “NAME SURNAME “,concat(‘Salary : ‘,salary) “SALARY” FROM hr.employees;

 

REPEATING ROWS

  • The DISTINCT command is used to list the repeating rows just one time.

 

  • Let’s list all departments of the company.

SELECT DISTINCT department_name FROM hr.departments;

 

VIEWING THE STRUCTURE OF TABLE

  • The DESCRIBE command is used to view the table structure.
  • DESC[RIBE] table_name;

 

  • Let’s list the structure of the hr.employees table.

DESC hr.employees;

 

You can continue to read from this link ;

One thought on “Oracle SQL Tutorials – Chapter 1 (Part 3 of 3)

  • June 17, 2019 at 11:13 am
    Permalink

    loved the site. “*” and “/” operators have equal precedence; and below them are “+” and “-” operators having equal precedence.

    Reply