Lesson 12 Intermediate Level
12 of 30 lessons

Built-in Functions

Learn about string, numeric, and date functions in Oracle SQL. Built-in functions are powerful tools for data manipulation and analysis.

What Are Built-in Functions?

Built-in functions in Oracle SQL help perform operations on data such as formatting, calculations, conversions, and summaries. These functions return either single results or grouped aggregates.

Types of Functions

  • Single Row Functions – operate on each row and return one result per row (e.g., UPPER, LOWER, LENGTH, SYSDATE)
  • Group Functions – operate on groups of rows and return a single result for each group (e.g., SUM, AVG, COUNT, MAX, MIN)

Examples

-- Convert name to uppercase
SELECT UPPER(first_name) FROM employees;

-- Get length of a name
SELECT LENGTH(first_name) FROM employees;

-- Count total employees
SELECT COUNT(*) FROM employees;

-- Calculate average salary
SELECT AVG(salary) FROM employees;

-- Get current date
SELECT SYSDATE FROM dual;

Practice Task

  • Display all employee names in lowercase using LOWER().
  • Show the maximum and minimum salaries from the employee table.
  • Find how many employees were hired in total using COUNT(*).
  • Use SYSDATE to display today’s date.
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