下面的代码抛出一个错误：“ORA-06502: PL/SQL: 数字或值错误 ORA-06512: 在第 24 行”。
DECLARE
v_clob CLOB;
CURSOR cur_a
IS
SELECT
device_num,
Account_number,
CustomerName,
Prem_address ,
contact_phone ,
W_status ,
A_status ,
"12-1 AM" Twelve21,
"1-2 AM" One22,
"2-3 AM" Two23,
"3-4 AM" Three24,
CIn4Hrs
FROM account a
WHERE 1 =1 ;
BEGIN
DBMS_LOB.CreateTemporary( v_clob, true );
FOR rec IN cur_a
LOOP
v_clob := v_clob ||rec.device_num|| ',' ||rec.Account_number|| ',' ||rec.contact_phone || ',' ||rec.W_status|| ',' ||rec.A_status|| ',' ||rec.Twelve21|| ',' ||rec.One22|| ',' ||rec.Two23|| ',' ||rec.Three24|| ',' ||rec.CIn4Hrs|| ',' ||SUBSTR(rec.CustomerName,1,15)|| …