mysql - 在mysql中创建存储过程时出错

Question

执行下面提到的脚本时出现错误

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 '$$

DROP PROCEDURE IF EXISTS `GetTopParentGivenDepth`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `GetTopParentGivenDepth`(GivenDepth INT)
BEGIN
    DECLARE X,Y,x1,x2 INT;
    SET X = 0;
    SET Y = 1;
    SET @SQ = 'SELECT DISTINCT A0.id FROM categories A0';
    WHILE Y < GivenDepth DO
        SET @SQ = CONCAT(@SQ,' INNER JOIN categories A',Y,' ON A',X,'.id = A',Y,'.parent_id');
        SET X = Y;
        SET Y = X + 1;
    END WHILE;
    SET @SQ = CONCAT(@SQ,' WHERE A0.parent_id = 0');
    SELECT @SQ;
    PREPARE stmt FROM @SQ;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;
END$$

Answer 1

创建过程之前缺少 DELIMITER

DELIMITER $$

DROP PROCEDURE IF EXISTS `GetTopParentGivenDepth`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `GetTopParentGivenDepth`(GivenDepth INT)
BEGIN
    DECLARE X,Y,x1,x2 INT;
    SET X = 0;
    SET Y = 1;
    SET @SQ = 'SELECT DISTINCT A0.id FROM categories A0';
    WHILE Y < GivenDepth DO
        SET @SQ = CONCAT(@SQ,' INNER JOIN categories A',Y,' ON A',X,'.id = A',Y,'.parent_id');
        SET X = Y;
        SET Y = X + 1;
    END WHILE;
    SET @SQ = CONCAT(@SQ,' WHERE A0.parent_id = 0');
    SELECT @SQ;
    PREPARE stmt FROM @SQ;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;
END$$

DELIMITER ;