Question

我尝试在MySQL中创建存储过程：

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;

但我收到错误：

您的SQL语法有错误;检查手册对应于您的MySQL服务器版本，以便使用正确的语法 'select _authorId = id from Authors where name = _authorName IF （_authorId在第1行是nul'

似乎脚本太大而无法执行。刚刚破线的行：
IF (_authorId is null) THEN - IF (_authorId is nul

Answer 1

您的分隔符存在问题。默认情况下，它是“;”。但是你需要内部分隔符，所以：

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

它在SQLYOG上的工作代码：请尝试这种方式

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 ;

无法执行SQL脚本语句（MySQL中的存储过程）

2 个答案: