Can I use it in SQL?

Yes, you can use the question mark (?) wildcard in SQL, but its usage depends on the database system you are working with. In SQL, the ? wildcard is typically used as a placeholder for a single character in certain SQL dialects, particularly in parameterized queries.

Usage in SQL

Parameterized Queries: In some database systems (like SQLite), the ? is used as a placeholder for parameters in prepared statements. For example:
```
SELECT * FROM users WHERE username LIKE 'A?B';
```
In this case, the query would match usernames like A1B, A2B, etc., where the ? can be replaced by any single character.
Using LIKE with Wildcards: However, for pattern matching in SQL, the more common wildcard is the underscore (_), which also represents a single character. For example:
```
SELECT * FROM users WHERE username LIKE 'A_B';  -- Matches 'A1B', 'A2B', etc.
```

Summary

While the ? wildcard can be used in certain contexts, it's more common to use the underscore (_) for single character matches in SQL queries. Always check the specific SQL dialect documentation you are using to confirm the correct usage.

If you have more questions or need further examples, feel free to ask!