请问写PL/SQL的块时怎么找到错误行？比如下面的错误报告，报告错误在line 18 和line 26.可是在Oracle SQL developer上实际找到的行分别是line 22和line 30.

SET SERVEROUTPUT ON;

DECLARE
v_current_custid hvc_hvvisitresult .so0_nrid%type;
v_prev_custid hvc_hvvisitresult.so0_nrid%type;
v_counter NUMBER;
v_totalcount NUMBER;

CURSOR sales_curs IS
SELECT *
FROM hvc_hvvisitresult
ORDER BY so0_nrid,visitdate;

BEGIN
FOR curs_rec IN sales_curs
LOOP

v_current_custid :=curs_rec.so0_nrid;

IF (v_current_custed=v_prev_custed) THEN v_counter:=v_counter+1;
ELSE v_counter:=1;
END IF;

IF v_counter=1 THEN
SELECT count(*) INTO v_totalcount FROM hvc_hvvisitresult WHERE so0_nrid=v_current_custid;
END IF;

IF v_counter=v_totalcount THEN DBMS_OUTPUT.PUT_LINE(curs_rec.so0_nrid||’ ’||cur_recs.amount||’ ’||curs_rec.visitdate);
END IF;

v_prev_custid:=v_current_custid;
END LOOP;

END;
/