How to get the previous date?

<span class="postbody" style="font-family: courier new,monospace;">Hi, <br /><br /> I'm using Enterprise DB
PostgresPlusversion 8.3. <br /> Is there is a simple function or command like previous_date(mydate) which when passed a
particulardate, simply returns the previous date? I tried <br /><br /> mydate - 1 <br /><br /> but this doesnt work.
<br/><br /> Thanks, <br /> Shruthi</span>