From the BO User Guide "Accessing Data and Data Analysis..."
Using wildcard characters
Conditions with the Match pattern and Different from pattern operators are great
for finding lists of similar values, such as customer names beginning with S.
Wildcards are special characters that can denote any single character, or any
number of characters. BusinessObjects supports the standard wildcard
characters, which are:
% Replaces several characters, or in the
response to a prompt. For example, N%
returns all values beginning with an N (New
York, Nevada)
_ Replaces a single character in a constant. For
example, GR_VE returns Grave, Grove,
Greve.