Using Functions

Purpose: Oracle provides numerous built-in functions for various data manipulations.Categories:

• String Functions:
  • UPPER(): Converts a string to uppercase.
  • LOWER(): Converts a string to lowercase.
  • SUBSTR(): Extracts a substring from a string.
  • LENGTH(): Returns the length of a string.
• Date Functions:
  • SYSDATE: Returns the current date and time.
  • ADD_MONTHS(): Adds a specified number of months to a date.
  • TRUNC(): Truncates a date to a specified unit (like day).
• Numeric Functions:
  • ROUND(): Rounds a number to a specified number of decimal places.
  • MOD(): Returns the remainder of a division operation.

Example:

SELECT UPPER(first_name) AS uppercase_name, ROUND(salary, 0) AS rounded_salary
FROM employees;

Explanation: This retrieves the first names in uppercase and the salaries rounded to the nearest whole number.