存储过程中的倒叙查询兑现不了么？desc

存储过程中的倒叙查询实现不了么？？desc
看代码

SQL code

drop procedure if exists query_news;delimiter $$ create procedure query_news(IN page_size int,IN page_num int,IN order_key varchar(30),IN order_flag int,OUT num int)begin    DECLARE start_pos int;    DECLARE seq varchar(5);    DECLARE ps int;    DECLARE ok varchar(30);        set @seq=order_flag;    set @ps=page_size;    set @ok=order_key;        set num=(select count(id) from news);    set @start_pos=page_size*(page_num-1);        if @seq=0 then    PREPARE STMT FROM 'select * from news  order by ?  desc limit ?,?;';     end if;        if @seq=1 then         PREPARE STMT FROM 'select* from news order by ? asc limit ?,?;';     end if;        EXECUTE STMT USING @ok,@start_pos,@ps;end$$delimiter ;

1.这是一个分页的查询存储过程
2.用变量标识排序列和分页参数
3.磁存储过程的int类型的参数1表示升序，0表示降序
4.调用 call query_news(10,1,'id',1,@out);
5.问题是无论第四个int类型的参数怎么变都只能升序排列
6.sql语句经过测试可以显示降序
7.news的建表语句如下

SQL code

create table news(   id                   bigint not null auto_increment,   catagory             char(3) not null,   pub_time             datetime not null,   publisher_id         tinyint not null,   title                char(50) not null,   content              text,   primary key (id));

[解决办法]
set @asql=concat('select * from news order by ',@ok,' desc limit ',@start_pos,',',@ps);
PREPARE STMT FROM @asql;
EXECUTE STMT;

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