I am working on an application of SGSV that searches a database of bibliographical information and returns a list of citations.One of the search fields is AUTHOR, and there are two ways that I need to implement the search.

1. There are multiple authors in the AUTHOR field, and I want to match any character string, i.e. any author: WHERE AUTHOR LIKE %'[PARM:AUTHOR]%'
2. There are multiple authors in the AUTHOR field, and I want to match the first author, i.e. the seach tries to match a character string at the beginning of the field: WHERE AUTHOR LIKE '[PARM:AUTHOR]%'

I would like to be able to select between these two options with a condition. So, there is a text field for the author and then there is a condition (check box) that, if checked, searches for the character string as the first author.

How might I go about implementing this?