What wildcard character is used specifically for a single character match in query expressions?

The wildcard character used specifically for a single character match in query expressions is the question mark. In many query languages and programming contexts, the question mark acts as a placeholder that represents exactly one character, allowing users to search for patterns where the length and specific characters of the match can vary.

For example, if you were searching for a string that contains a specific letter followed by any single character and then another specific letter (like "a?c"), the question mark would match any one character between "a" and "c", such as "abc", "axc", or "a1c". This feature is particularly useful when dealing with variable data entries or when the exact character occurring in a specific position isn't known, but the pattern remains consistent.

In contrast, the asterisk is generally used to represent zero or more characters, making it suitable for broader searches rather than matching a single character. The terms LINK and NOTLIKE do not pertain to wildcard character matching in this context and have different roles in query expressions, typically relating to data relationships or filtering criteria rather than pattern matching.