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create table products(
prod_id int primary key,
prod_price int not null,
total_prod_amt int );
create or replace trigger total_amt
after insert or delete or update
on products
for each row
BEGIN
update products
SET products.total_prod_amt=
(SELECT SUM(products.prod_price)
FROM products
WHERE products.prod_id=products.prod_id
);
END;
/
select * from user_errors;
insert into products(prod_id, prod_price) values (1,10);
ORA-04091: table FIDDLE_DRLOPQIBFWCYUAPCXKVV.PRODUCTS is mutating, trigger/function may not see it
ORA-06512: at "FIDDLE_DRLOPQIBFWCYUAPCXKVV.TOTAL_AMT", line 2
ORA-04088: error during execution of trigger 'FIDDLE_DRLOPQIBFWCYUAPCXKVV.TOTAL_AMT'