Answers and Solutions

Answer

A wildcard character is a special character that represents one or more othercharacters. The most commonly used wildcard characters are the asterisk (*), which typically represents zero or more characters in a string of characters, and the question mark (?), which typically represents any one character.

Answer

wildcard character, a wildcard is a symbol used to replace or represent one or more characters. Wildcards are typically either an asterisk (*), which represents one or more characters or question mark (?), which represents a single character. In the examples below of how a wildcard may be used, realize that wildcards are relatively universal.

Wildcard basics

 Percent ( % ) in a wildcard

 The percent symbol is used in SQL to match any character (including an underscore) zero or more times.

 Asterisk ( * ) in a wildcard

 The asterisk in a wildcard matches any character zero or more times. For example, "comp*" matches anything beginning with "comp" which means "comp", "complete", and "computer" are all matched.

 Question mark ( ? ) in a wildcard

 A question mark matches a single character once. For example, "c?mp" matches "camp" and "comp". The question mark can also be used more than once. For example, "c??p" would match both of the above examples as well as "coop". In MS-DOS and the Windows command line the question mark also can match any trailing question marks zero or one times. For example, "co??" would match all of the above matches, but because they are trailing question marks would also match "cop" even though its not four characters.

 Tip: With regular expressions a period ( . ) is a wildcard for a single character.

 Open and close brackets ( [ ] ) in a wildcard

 With Unix shells, Windows PowerShell, and programming languages that support regular expressions the open and close bracket wildcards match a single character in a range. For example, [a-z] matches any character "a" through "z", which means anything not in that range like a number would not be matched.

 Tip: Adding an exclamation in places that support the brackets as a wildcard will tell the program to NOT match.