Which wildcard character in SQL represents zero or more characters?

The wildcard character in SQL that represents zero or more characters is the percent sign (%). In SQL, the percent sign is used in conjunction with the LIKE operator to search for patterns in string data. For example, if you use the query SELECT * FROM Employees WHERE Name LIKE 'A%', it will return all employees whose names start with the letter 'A' regardless of what follows. This includes cases where there are no additional characters, effectively meaning it can match an empty string as well.

The percent sign is particularly powerful because it allows for flexible pattern matching. It can match any sequence of characters, including no characters at all, making it useful for various querying scenarios such as searching for any records that contain certain substrings or prefixes. Understanding this usage is crucial for effectively employing SQL in database management and querying.