combining search fields into one

Hi

I've used DA to create search/results pages. Currently there are 3 search boxes, for the fields PgTitle, PgDesc and PgDetails.

This search works fine (additional parameters are used to restrict records to SiteID etc).

What I would like to do is have one search field, which looks for matches in any of those 3 fields.

I've tried changing the following in different ways:

//comparison list additions
$WADbSearch1->addComparisonFromEdit("PgTitle","S_PgTitle","AND","Includes",0);
$WADbSearch1->addComparisonFromEdit("PgDesc","S_PgDesc","AND","Includes",0);
$WADbSearch1->addComparisonFromEdit("PgDetails","S_PgDetails","AND","Includes",0);

However, when I try to combine them into one, I either get ALL records for the particular SiteID or no records (even though I am testing with criteria I know should work).

ANy suggestions? I might well be looking at the wrong piece of code - but I can't see anything else that looks likely.

Many thanks
Chris