NULL Handling & COALESCE Function — Free SQL Tutorial
Learn NULL Handling & COALESCE Function in SQL with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.
TL;DR: Learn NULL Handling & COALESCE Function in SQL with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
NULL Handling & COALESCE Function in SQL
NULL represents missing or unknown data — it's not zero, not empty string, not false. IS NULL and IS NOT NULL are the only ways to check for NULL.
COALESCE(expr1, expr2, expr3, ...) returns the first non-NULL value. Useful for providing defaults, handling missing data in JOINs.
IFNULL (MySQL) and NVLEVEL (Oracle) are single-argument alternatives. Arithmetic with NULL always returns NULL.
NULL Handling & COALESCE Function — Syntax
WHERE column IS NULL WHERE column IS NOT NULL COALESCE(col1, col2, col3, 'default') IFNULL(col, 'default') -- MySQL only
Learn NULL Handling & COALESCE Function step by step with Syllab's free interactive SQL tutorial — runnable code examples, practice exercises and instant AI feedback, all free with no signup. Explore the full SQL course →