为什么我的MySQL程序应该选择一个随机行,而只选择三个特定值中的一个?

我有一个名为 quote_of_the_day 它应该从列表中选择不同的行 quotes 表中的日期作为种子值。当我将代码作为查询进行测试时,一切似乎都运行良好,但当我在php代码中调用函数时(查询是 CALL quote_of_the_day() )它只会从三个不同的引号中选择一个,尽管表中有23个引号。

创建systax for 引用今天的话 是:

DELIMITER ;;
CREATE DEFINER=`root`@`%` PROCEDURE `quote_of_the_day`()
BEGIN
        # save the number of rows into a variable
        SET @num_rows = (SELECT COUNT(*) FROM `quotes`);

        # calculate a random number no greater than the number of rows in the table
        SET @rand_num = (SELECT FLOOR(RAND(CURDATE())*(@num_rows+1)));

        # select random quote from the list of quotes (seed value is the current day)
        SELECT quote FROM quotes WHERE id = @rand_num;
        
        # increment the quoted column to keep track of which quotes are selected
        UPDATE quotes SET quoted = quoted + 1 WHERE id = @rand_num AND last_used <> CURDATE();
        UPDATE quotes SET last_used = CURDATE() WHERE id = @rand_num;
    END;;
DELIMITER ;

我哪里做错了?