Failed to execute SQL script statement (stored procedure in MySQL) - mysql

Question

I try to create stored procedure in MySQL:
create PROCEDURE sp_attachAuthorToBook(
IN _bookId INT,
IN _authorName VARCHAR(20)
)
BEGIN
declare _authorId int
select _authorId = id from Authors where name = _authorName
IF (_authorId is null) THEN
INSERT INTO Authors (name)
VALUES (_authorName)
SELECT _authorId = SCOPE_IDENTITY()
END IF
insert into Books_Authors (bookID, authorID)
values (_bookId, _authorId)
END;
But I get the error:
You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near 'select _authorId = id from Authors where name = _authorName IF
(_authorId is nul' at line 1
Seems like script is too large to be executed. Line just broken near: IF (_authorId is null) THEN -- IF (_authorId is nul

Answer 1

You have a problem with your delimiters. By default it's ";". But you need internal delimiter, so :
DELIMITER |
create PROCEDURE sp_attachAuthorToBook(
IN _bookId INT,
IN _authorName VARCHAR(20)
)
BEGIN
declare _authorId int;
select _authorId = id from Authors where name = _authorName;
IF (_authorId is null) THEN
INSERT INTO Authors (name)
VALUES (_authorName);
SELECT _authorId = LAST_INSERT_ID();
END IF;
insert into Books_Authors (bookID, authorID)
values (_bookId, _authorId);
END|

Answer 2

Its working code on SQLYOG: Please try in this way
DELIMITER $$
CREATE /*[DEFINER = { user | CURRENT_USER }]*/ PROCEDURE `test`.`sp_attachAuthorToBook`(
IN _bookId INT,
IN _authorName VARCHAR(20)
)
BEGIN
DECLARE _authorId INT;
SELECT id INTO _authorId FROM Authorss WHERE `name` = _authorName;
IF _authorId IS NULL THEN
INSERT INTO Authorss(`name`) SELECT _authorName;
SET _authorId = LAST_INSERT_ID();
END IF;
INSERT INTO Book_Authors(bookID, authorID) SELECT _bookId, _authorId;
END$$
DELIMITER ;