SQL Aliases

Aliases — short names for columns and tables

An alias renames a column or table in the result only — it does not change the database. Use AS for clarity; AS is optional on many databases.

Table aliases (s, c, e) shorten queries and are required when the same table appears twice.

Real-life example: Aliases are nicknames in a classroom — 'Ravi P.' on the attendance sheet instead of the full legal name every time.

SELECT
  full_name AS student_name,
  grade_level AS grade
FROM students AS s
WHERE s.city = 'Delhi';

SELECT
  c.course_name AS subject,
  e.score AS marks
FROM enrollments e
JOIN courses c ON e.course_id = c.course_id;