TRUNCATE `TICKETLINES`;
TRUNCATE `TICKETS`;
TRUNCATE `PAYMENTS`;
TRUNCATE `TAXLINES`;
TRUNCATE `RECEIPTS`;
TRUNCATE `CLOSEDCASH`;
TRUNCATE `STOCKDIARY`;
TRUNCATE `STOCKCURRENT`;
TRUNCATE `RESERVATION_CUSTOMERS`;
TRUNCATE `RESERVATIONS`;
update TICKETSNUM set ID = 1;
update PRODUCTS set stockcost=0, stockvolume=0;
update CUSTOMERS set curdebt=0, curdate=null;

http://wiki.openbravo.com/wiki/Projects/POS/Administrator_Guide#Clearing_Data

THIS PROCESS WILL CLEAR YOUR TRANSACTION DATA.
Openbravo POS. Clearing transaction data can be achieved with this SQL. This may be desirable in a new deployment when all products are loaded, staff have been trained and test runs are complete. This step would be taken when going live.

Openbravo POS - Clearing transaction data

SQL