mysql - From 在此位置无效，应为 : ';' in mysql

Question

我正在学习如何在 MySQL 中创建存储过程，但在创建过程中出现错误。

这是我的存储过程:

CREATE DEFINER=`root`@`localhost` PROCEDURE `GetCategoryWiseProducts`(IN param varchar(250), IN isAll boolean)
BEGIN
    declare catName VARCHAR(250) default '';
    declare catId VARCHAR(250) default 0;

    IF(isAll) THEN
        SELECT 'All Products' as category_name, COUNT(*) as total from product_mast;
    ELSE 
        SELECT category_name INTO catName, category_id INTO catId from category_mast WHERE slug = param;
        SELECT catName as category_name, COUNT(*) as total from product_mast WHERE category_id = @category_id;
    END IF;
END;

遇到错误

from is not valid at this position, expecting : ';'

在 else 语句的第一个查询中。

Answer 1

使用DELIMITER，参见24.1 Defining Stored Programs :

DELIMITER //

CREATE DEFINER ... PROCEDURE ...
BEGIN
  ...
  -- SELECT category_name INTO catName, category_id INTO catId from category_mast WHERE slug = param;
  SELECT category_name, category_id INTO catName, catId
  from category_mast
  WHERE slug = param;
  ...
END//

DELIMITER ;

@category_id 变量集的值在哪里？