在 mySQL 工作台中创建过程语句时出现错误 1064

Question

这是我认为可以正常运行的过程语句的代码，但我无法运行它，因为我不断收到此错误：Error Code: 1064。您的 SQL 语法有错误；检查与您的 MariaDB 服务器版本相对应的手册，以了解在 ') 附近使用的正确语法； ——发放新贷款。在第 70 行插入贷款（code，no，采取，到期）VA'

我试图找到修复它的方法，但我没有找到任何东西。其他人可以看到我是否写错了，或者我在我看不到的地方的代码中犯了任何错误吗？错误将我发送到第 70 行，但 FETCH NEXT FROM copy_c INTO copy_code; 告诉我 FROM 不在正确的位置。我还包括我的 cmets，以便更轻松地阅读此代码。

DELIMITER $$

          CREATE PROCEDURE `new_loan` (IN book_isbn CHAR(17), IN student_no INT)

          BEGIN

        -- search for the copy of the book and test for loan record in loan table.
        DECLARE copy_code, loan_test INT;

        -- test for successful loan and for end of cursor.
        DECLARE inserted, complete BOOLEAN;


        -- the duration date and current date for new loan issue and number of days for the new loan.
        DECLARE due, cur DATE;
        DECLARE copy_dur TINYINT;

        -- test if students can loan books.
    DECLARE embargo_status BIT(1) DEFAULT b'1';

    -- cursor for copy codes based on isbn.
    DECLARE copy_c CURSOR FOR
        SELECT `code`
        FROM copy
        WHERE isbn = book_isbn;

        DECLARE CONTINUE HANDLER FOR NOT FOUND
            SET complete = TRUE;


        OPEN copy_c;

        -- get student embargo status.
        SET embargo_status = (SELECT embargo 
                    FROM student
                    WHERE `no` = student_no);

        SELECT embargo_status;

        -- check if the student is valid or embargo is no, if not report a message.
        IF (embargo_status IS NULL OR embargo_status = b'1') THEN
            SIGNAL SQLSTATE '45000'
                SET MESSAGE_TEXT = 'The student is not valid or has embargo!';
        END IF;

        SET inserted = FALSE;
        SET copy_code = 0;

        -- loop through copies to see when that is available.
        copy_codes: LOOP
        FETCH NEXT FROM copy_c INTO copy_code;

        IF complete THEN 
            SIGNAL SQLSTATE '45000'
                SET MESSAGE_TEXT = 'We looped to end and found nothing!';
        END IF;

        -- if a copy is available then loan_test will be null.  
        -- if return is null the book is out on loan and a non null value will be returned to loan_test.
        SET loan_test = (SELECT `code` FROM loan
                    WHERE (`code` = copy_code) AND (`return` IS NULL));

        -- if a copy is available loan_test will be null.  
    -- A null value implies that the copy had a one or many records in loan with a non null return or the copy was never out on loan.
        IF (loan_test IS NULL) THEN     
            SET cur = CURRENT_DATE();
            SET copy_dur = (SELECT duration 
                     FROM copy
                     WHERE `code` = copy_code);

        -- calculate due date.
        SET due = DATE_ADD (cur, INTERVAL copy_dur DAY);


        -- issue the new loan.
        INSERT INTO loan (`code`, `no`, taken, due)
                VALUES (copy_code, student_no, cur, due);

        SET inserted = TRUE;

        LEAVE copy_codes;

        END IF;

        END LOOP;

        CLOSE copy_c;

        -- inform users of a failed loan.
        IF (inserted = FALSE) THEN 
            SIGNAL SQLSTATE '45000'
                SET MESSAGE_TEXT = 'No currently available copies or book does not exist! '; 
        END IF;

    END$$

    DELIMITER ;

Answer 1

MySQL Workbench 会为您提供包含详细信息的错误消息。你没看到吗？实际上，它给了你 2 个错误，但第一个（关于 FETCH NEXT）是 WB 语法检查器中的一个错误，将在下一个版本中修复。

第二个说：

“DATE_ADD”在此位置无效，需要完整的函数调用或其他表达式。

有什么比来自 MySQL（或 MariaDB）的那些丑陋的错误消息更好地描述了问题所在。当您查看该调用时，您会看到左括号前有一个空格，由于SQL mode IGNORE_SPACE 而改变了含义。删除空格字符，您的 SP 将被接受。