CREATE OR REPLACE TRIGGER invoice_before_delete
BEFORE DELETE
ON prj_invoice_work_exe
FOR EACH ROW
DECLARE
v_username varchar2(10);
BEGIN
SELECT user INTO v_username
FROM dual;
INSERT INTO prj_invoice_work_exe1
( PIE_PIN_ID,PIE_TDT_ID,PIE_ID,PIE_QTY_EXECUTED,PIE_UNIT_PRICE,PIE_NET_PRICE,PIE_INVOICED_AMOUNT,PIE_UNT_CODE,PIE_HST_UNIT_PRICE,
PIE_HST_TOTAL_QTY,PIE_HST_TOTAL_BILLED_QTY,PIE_HST_ALLOW_TO_BILL_QTY,PIE_HST_PRCT_OF_COMPLETION,PIE_HST_QTY_COMPLETED,
PIE_PWR_ID,PIE_DISCOUNT,PIE_DOWN_PAYMENT_RECOVERY,PIE_BOQ_DISCOUNT,PIE_BOQ_DOWN_PAYMENT,PIE_UNT_PRICE_BFR_DISCOUNT,
PIE_TOTAL_PRICE_BFR_DISCOUNT )
VALUES
( :old.PIE_PIN_ID,old.PIE_TDT_ID,old.PIE_ID,old.PIE_QTY_EXECUTED,old.PIE_UNIT_PRICE,old.PIE_NET_PRICE,old.PIE_INVOICED_AMOUNT,old.PIE_UNT_CODE,old.PIE_HST_UNIT_PRICE,
old.PIE_HST_TOTAL_QTY,old.PIE_HST_TOTAL_BILLED_QTY,old.PIE_HST_ALLOW_TO_BILL_QTY,old.PIE_HST_PRCT_OF_COMPLETION,old.PIE_HST_QTY_COMPLETED,
old.PIE_PWR_ID,old.PIE_DISCOUNT,old.PIE_DOWN_PAYMENT_RECOVERY,old.PIE_BOQ_DISCOUNT,old.PIE_BOQ_DOWN_PAYMENT,old.PIE_UNT_PRICE_BFR_DISCOUNT,
old.PIE_TOTAL_PRICE_BFR_DISCOUNT, sysdate, v_username );
END;
/

and it shows the compiling error!