'RAISERROR' must be declared - mysql

Question

CREATE TRIGGER x AFTER INSERT ON itemtype
FOR EACH ROW
DECLARE
minn itemtype.PRICE%type;
BEGIN
select MIN(itemtype.PRICE) into minn from itemtype;
IF (:new.PRICE > minn*4) then RAISERROR('Custom text');
END IF;
END;
/
I'm trying to create a trigger that raises an error when I try to insert a new entry into the itemtype with itemtype.PRICE column value is greater than 4 times the current low priced item on the table.
I get these compilation errors when I try to create the trigger.
LINE/COL ERROR
-------- --------------------------------------------------------------
5/31 PL/SQL: Statement ignored
5/31 PLS-00201: identifier 'RAISERROR' must be declared
I have also tried
CREATE TRIGGER x AFTER INSERT ON itemtype
FOR EACH ROW
DECLARE
minn itemtype.PRICE%type;
BEGIN
select MIN(itemtype.PRICE) into minn from itemtype;
if (:new.PRICE > minn*4) then raise_application_error(-20010,'Too Expensive');
END IF;
END;
/
which complies, but when i try to insert a new entry into the table I get theses errors saying my trigger fails.
SQL> insert into itemtype(ITEMNUM,NAME,PICTURE,PRICE,BELONGSTO ) VALUES ('A11','The who knows','',10.99,'P');
insert into itemtype(ITEMNUM,NAME,PICTURE,PRICE,BELONGSTO ) VALUES ('A11','The who knows','',10.99,'P')
*
ERROR at line 1:
ORA-04091: table USERNAME.ITEMTYPE is mutating, trigger/function may not see it
ORA-06512: at "USERNAME.X", line 5
ORA-04088: error during execution of trigger 'USERNAME.X'

Answer 1

Try use PRAGMA AUTONOMOUS_TRANSACTION in trigger.
Look my answer on this question:
SQL trigger on delete mutating table