Single-Row SQL Functions

String Functions

SELECT UPPER(first_name), LOWER(last_name) FROM employees;

SELECT SUBSTRING(email, 1, 5) FROM employees;

SELECT LENGTH(first_name) FROM employees;

SELECT CONCAT(first_name, ' ', last_name) AS full_name FROM employees;

SELECT ROUND(salary, 2) FROM employees;

SELECT ABS(difference) FROM calculations;

SELECT MOD(employee_id, 2) FROM employees;

SELECT NOW() AS current_time;

SELECT DATE_FORMAT(hire_date, '%Y-%m-%d') FROM employees;

SELECT DATEDIFF(NOW(), hire_date) AS days_employed FROM employees;

SELECT salary,
  CASE
    WHEN salary > 80000 THEN 'High'
    WHEN salary > 50000 THEN 'Medium'
    ELSE 'Low'
  END AS salary_grade
FROM employees;

SELECT COALESCE(middle_name, 'N/A') FROM employees;