Hello Chandra, First thing the revision tables is:

po_headers_all, po_headers_archive_all, po_lines_archive_all, po_line_locations_archive_all and po_distributions_archive_all

Note: How the Purchasing Archive tables are updated when using Archive on Approve method for archiving (To setup Archive on Approve go to Setup -> Purchasing -> Document Types) and here an example to understand and to get the revision’s of PO 1- We created new PO, sent it for approval 2- PO Approved Now run this query :

SELECT po_header_id, segment1, revision_num 
FROM po_headers_all 
WHERE po_header_id = &p_po_header_id

which is (&p_po_header_id) is ID for po has been created above. and here is the result expected:

3- Now add a new line in PO, then sent it for reapproval. 4- PO Approved Now run this query

SELECT po_header_id, segment1, revision_num 
FROM po_headers_archive_all 
WHERE po_header_id = &p_po_header_id

So now from archive table you can get all revisions for particular PO.