Oracle SQL.

INstructions: Write a PL/SQL function that returns the average retail price of all of the books in the books table.

I have this so far but i keep receiving errors:

Create Function GetPrice RETURN NUMERIC(9, 2) AS BEGIN

DECLARE @avgRetailPrice AS NUMERIC(9, 2); SELECT @avgRetailPrice = CAST(AVG(retail) AS NUMERIC(9, 2))

FROM BOOKS;

RETURN @AvgRetailPrice;

END

Attached is the BOOKS table and data:

CREATE TABLE Books (ISBN VARCHAR2(10), Title VARCHAR2(30), PubDate DATE, PubID NUMBER (2), Cost NUMBER (5,2), Retail NUMBER (5,2), Discount NUMBER (4,2), Category VARCHAR2(12), CONSTRAINT books_isbn_pk PRIMARY KEY(isbn), CONSTRAINT books_pubid_fk FOREIGN KEY (pubid) REFERENCES publisher (pubid)); INSERT INTO BOOKS VALUES ('1059831198','BODYBUILD IN 10 MINUTES A DAY','21-JAN-05',4,18.75,30.95, NULL, 'FITNESS'); INSERT INTO BOOKS VALUES ('0401140733','REVENGE OF MICKEY','14-DEC-05',1,14.20,22.00, NULL, 'FAMILY LIFE'); INSERT INTO BOOKS VALUES ('4981341710','BUILDING A CAR WITH TOOTHPICKS','18-MAR-06',2,37.80,59.95, 3.00, 'CHILDREN'); INSERT INTO BOOKS VALUES ('8843172113','DATABASE IMPLEMENTATION','04-JUN-03',3,31.40,55.95, NULL, 'COMPUTER'); INSERT INTO BOOKS VALUES ('3437212490','COOKING WITH MUSHROOMS','28-FEB-04',4,12.50,19.95, NULL, 'COOKING'); INSERT INTO BOOKS VALUES ('3957136468','HOLY GRAIL OF ORACLE','31-DEC-05',3,47.25,75.95, 3.80, 'COMPUTER'); INSERT INTO BOOKS VALUES ('1915762492','HANDCRANKED COMPUTERS','21-JAN-05',3,21.80,25.00, NULL, 'COMPUTER'); INSERT INTO BOOKS VALUES ('9959789321','E-BUSINESS THE EASY WAY','01-MAR-06',2,37.90,54.50, NULL, 'COMPUTER'); INSERT INTO BOOKS VALUES ('2491748320','PAINLESS CHILD-REARING','17-JUL-04',5,48.00,89.95, 4.50, 'FAMILY LIFE'); INSERT INTO BOOKS VALUES ('0299282519','THE WOK WAY TO COOK','11-SEP-04',4,19.00,28.75, NULL, 'COOKING'); INSERT INTO BOOKS VALUES ('8117949391','BIG BEAR AND LITTLE DOVE','08-NOV-05',5,5.32,8.95, NULL, 'CHILDREN'); INSERT INTO BOOKS VALUES ('0132149871','HOW TO GET FASTER PIZZA','11-NOV-06',4,17.85,29.95, 1.50, 'SELF HELP'); INSERT INTO BOOKS VALUES ('9247381001','HOW TO MANAGE THE MANAGER','09-MAY-03',1,15.40,31.95, NULL, 'BUSINESS'); INSERT INTO BOOKS VALUES ('2147428890','SHORTEST POEMS','01-MAY-05',5,21.85,39.95, NULL, 'LITERATURE');