为何触发器有时报错，有时不报错？很急，谢谢！
我有两张表
create table STD_STATS_TOTAL
(
SWITCH_ID NUMBER(4),
CALLING_DATE CHAR(14),
CALLING_TIME CHAR(2),
EXCHANGE_CODE VARCHAR2(6),
COUNTS NUMBER(14)
);
create table WW_TEST
(
SWITCH_ID NUMBER(4),
CALLING_DATE CHAR(14),
CALLING_TIME CHAR(2),
EXCHANGE_CODE VARCHAR2(6),
COUNTS NUMBER(14)
);
insert into WW_TEST (SWITCH_ID, CALLING_DATE, CALLING_TIME, EXCHANGE_CODE, COUNTS)
values (1001, '20050720', '18', 'total', 10);
我对STD_STATS_TOTAL表建一个触发器
-------------以下是触发器-------------
create or replace trigger befor_ins_std_stats_total
before insert on std_stats_total
for each row
declare
v_counts number(14);
begin
select sum(counts)
into v_counts
from std_stats_total
where switch_id = :new.switch_id and calling_date = :new.calling_date
and exchange_code = :new.exchange_code and calling_time = :new.calling_time ;
if v_counts != 0
then
delete from std_stats_total
where switch_id = :new.switch_id and calling_date = :new.calling_date
and exchange_code = :new.exchange_code and calling_time = :new.calling_time ;
:new.counts := v_counts + :new.counts;
end if ;
end befor_ins_std_stats_total;
-----------------以上是触发器-------------------
这个触发器的功能是当插入一条记录时，检查表中是否有除了counts外，其他字段一样的记录，如果有的话，就将counts值相加，原来的记录删去。
我执行：
insert into std_stats_total values (1001,'20050720','18','total',10);
语句的时候，触发器正常执行。
但我执行这样的语句：insert into std_stats_total select * from ww_test;的时候却报错：
SQL>
insert into std_stats_total select * from ww_test
ORA-04091: table BILL.STD_STATS_TOTAL is mutating, trigger/function may not see it
ORA-06512: at "BILL.BEFOR_INS_STD_STATS_TOTAL", line 6
ORA-04088: error during execution of trigger 'BILL.BEFOR_INS_STD_STATS_TOTAL'
Commit complete
SQL>
为何插入有具体值的记录时不报错，从表里查数据插入的时候要报错？要怎样修改？
问题点数：20、回复次数：2Top
1 楼zjw7789（随风）回复于 2005-07-25 16:50:38 得分 20
逻辑错误:
以插入数据之前为触发条件的触发器不允许对载体表进行sum操作
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2 楼robinww（robinww）回复于 2005-07-26 16:14:07 得分 0
但是我用insert into std_stats_total values (1001,'20050720','18','total',10);这样的语句时，触发器是可以执行的呀？
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