Query on Oracle 10g Merge Function equivalent command/function in Postgre

Query on database migration<BR>--------------------------------<BR>&nbsp;&nbsp;<BR>We are thinking of migrating one application from Oracle 10g to <BR>Postgre environment. We are using Oracle 10g Merge functionality to comprae <BR>and&nbsp;filter out the &nbsp;records into two groups. The master database <BR>size&nbsp;is having&nbsp;about 11 million records and comparision table which <BR>is to be compared can have upto 130000 records. This is a <BR>continous process and daily some 1200 such comparisns are done.<BR><BR>Could you guide me if their is any equivalent functionality to <BR>that of Oracle Merge function available in any of the postgre version or any best way to do this task to get maximum throughputand performance. <BR><BR>Your reply would be highly appreciated.&nbsp;<BR><BR>with regards, <BR><BR>I.P.S. Sethi <BR>Technical Director, <BR>National Informatics Centre, <BR>Department of Information Technology, <BR>New Delhi. <BR><BR>