To search for the occurrence of %, _, [, ], or ^ within a string, you must use an escape character. When a wildcard character is used in conjunction with an escape character, Adaptive Server interprets the wildcard character literally, rather than using it to represent other characters.
Adaptive Server provides two types of escape characters:
Square brackets, a Transact-SQL extension
Any single character that immediately follows an escape clause, compliant with the SQL standards