Using Wildcard Filtering - MariaDB Crash Course - page 60

The Underscore ( _ ) Wildcard
Another useful wildcard is the underscore ( _ ). The underscore is used just like
% , but instead of matching multiple characters, the underscore matches just a
single character.
Take a look at this example:
▼ Input
SELECT prod_id, prod_name
FROM products
WHERE prod_name LIKE '_ ton anvil';
▼ Output
+---------+-------------+
| prod_id | prod_name |
+---------+-------------+
| ANV02 | 1 ton anvil |
| ANV03 | 2 ton anvil |
+---------+-------------+
▼ Analysis
The search pattern used in this WHERE clause specifies a wildcard followed by
literal text. The results shown are the only rows that match the search pattern:
The underscore matches 1 in the first row and 2 in the second row. The .5
ton anvil product did not match because the search pattern matched a single
character, not two. By contrast, the following SELECT statement uses the %
wildcard and returns three matching products:
▼ Input
SELECT prod_id, prod_name
FROM products
WHERE prod_name LIKE '% ton anvil';
▼ Output
+---------+--------------+
| prod_id | prod_name |
+---------+--------------+
| ANV01 | .5 ton anvil |
| ANV02 | 1 ton anvil |
| ANV03 | 2 ton anvil |
+---------+--------------+
Unlike % , which can match zero characters, _ always matches one character—
no more and no less.