Wildcard Matching (Pattern Matching)

tags: #sql

How is pattern matching used?

The LIKE operator is used in a WHERE clause to search for a specified pattern in a column.

There are two wildcards^[1] often used in conjunction with the LIKE operator:

• The percent sign (%) represents zero, one, or multiple characters
• The underscore sign (_) represents one, single character

How do we use it in practice?

Consider the following:

SELECT * 
FROM table_name 
WHERE name LIKE 'J%';

Here, this will return all records where the "name" column starts with the letter "J", followed by any number of characters.

Finding records with a specific character in the value

SELECT *
FROM table_name
WHERE name LIKE %J% // can also be a sequence of characters e.g., %son%
...

// OR
...
WHERE ssn LIKE '_ _ _ 1 _'
...