Wildcards

Wildcards are special characters used with the LIKE operator to search for patterns within text data, instead of requiring an exact match.

The Two Main Wildcards

• % - matches zero, one, or many characters
• _ - matches exactly one character

Using LIKE with %

-- Names starting with "Ri"
SELECT * FROM customers WHERE first_name LIKE 'Ri%';

-- Emails ending in "@gmail.com"
SELECT * FROM customers WHERE email LIKE '%@gmail.com';

-- Names containing "an" anywhere
SELECT * FROM customers WHERE first_name LIKE '%an%';

Using LIKE with _

-- Four-letter names starting with "R"
SELECT * FROM customers WHERE first_name LIKE 'R___';

Case Sensitivity

Whether LIKE is case-sensitive depends on the database system and its configured collation - MySQL is typically case-insensitive by default, while PostgreSQL's LIKE is case-sensitive (use ILIKE there instead).