Only clear (avoid documents' number colision)

clear orders

clear db

SET FOREIGN_KEY_CHECKS=0;

TRUNCATE `sales_flat_order`;
TRUNCATE `sales_flat_order_address`;
TRUNCATE `sales_flat_order_grid`;
TRUNCATE `sales_flat_order_item`;
TRUNCATE `sales_flat_order_payment`;
TRUNCATE `sales_flat_order_status_history`;

TRUNCATE `sales_flat_quote`;
TRUNCATE `sales_flat_quote_address`;
TRUNCATE `sales_flat_quote_address_item`;
TRUNCATE `sales_flat_quote_item`;
TRUNCATE `sales_flat_quote_item_option`;
TRUNCATE `sales_flat_order_item`;
TRUNCATE `sendfriend_log`;																																																																																																								
TRUNCATE `tag`;
TRUNCATE `tag_relation`;
TRUNCATE `tag_summary`;
TRUNCATE `wishlist`;
TRUNCATE `log_quote`;
TRUNCATE `report_event`;
TRUNCATE `tag_relation`;
TRUNCATE `tag_summary`;
TRUNCATE `wishlist`;
TRUNCATE `log_quote`;
TRUNCATE `report_event`;

TRUNCATE `sales_flat_shipment`;
TRUNCATE `sales_flat_shipment_comment`;
TRUNCATE `sales_flat_shipment_grid`;
TRUNCATE `sales_flat_shipment_item`;

TRUNCATE `sales_flat_invoice`;
TRUNCATE `sales_flat_invoice_comment`;
TRUNCATE `sales_flat_invoice_grid`;
TRUNCATE `sales_flat_invoice_item`;

TRUNCATE `sales_flat_creditmemo`;
TRUNCATE `sales_flat_creditmemo_comment`;
TRUNCATE `sales_flat_creditmemo_grid`;
TRUNCATE `sales_flat_creditmemo_item`;

TRUNCATE `sales_flat_quote_shipping_rate`;

TRUNCATE `sales_order_tax`;
TRUNCATE `sales_order_tax_item`;

TRUNCATE `sales_shipping_aggregated_order`;
TRUNCATE `sales_shipping_aggregated`;
TRUNCATE `sales_order_aggregated_updated`;
TRUNCATE `sales_order_aggregated_created`;
TRUNCATE `sales_invoiced_aggregated_order`;
TRUNCATE `sales_invoiced_aggregated`;

SET FOREIGN_KEY_CHECKS=1;