mysql存储过程在动态SQL内获取返回值的方法详解

 $:begin
    declare v_sqlcounts varchar(4000);
    declare v_sqlselect varchar(4000);
 #拼接查询总记录的SQL语句
   set v_sqlcounts = concat('select count(*) into @recordcount from ',p_tables,p_where);
    #select v_sqlcounts;leave $;
   set @sqlcounts = v_sqlcounts;
   prepare stmt from @sqlcounts;
        execute stmt;
  deallocate prepare stmt;
   #获取动态SQL语句返回值
  set p_recordcount = @recordcount;
  #根据总记录跳数计算出总页数
   set p_pagecount = ceiling((p_recordcount+0.0)/p_pagesize);
   if p_pageindex <1 then
       set p_pageindex = 1;
     elseif p_pageindex > p_pagecount and p_pagecount <> 0 then
       set p_pageindex = p_pagecount;
   end if;
   #拼接分页查询记录的动态SQL语句
   set v_sqlselect = concat('select ',p_cloumns,' from ',p_tables,p_where,if(p_order is not null,p_order,''),' limit ',(p_pageindex-1)*p_pagesize,' , ',p_pagesize);
   #select v_sqlselect;leave $;
   set @sqlselect = v_sqlselect;
    prepare stmtselect from @sqlselect;
   execute stmtselect;
    deallocate prepare stmtselect;
   end $

代码如下:
#拼接查询总记录的SQL语句  
set v_sqlcounts = concat('select count(*) into @recordcount from ',v_tables,v_where);  
set @sqlcounts := v_sqlcounts;  
#预处理动态SQL  
prepare stmt from @sqlcounts;  
#传递动态SQL内参数  
set @s1= categoryid;  
execute stmt using @s1;  
deallocate prepare stmt;  
#获取动态SQL语句返回值  
set recordcount = @recordcount; 

#拼接查询总记录的SQL语句
set v_sqlcounts = concat('select count(*) into @recordcount from ',v_tables,v_where);
set @sqlcounts := v_sqlcounts;
#预处理动态SQL
prepare stmt from @sqlcounts;
#传递动态SQL内参数
set @s1= categoryid; execute stmt using @s1; deallocate prepare stmt;
#获取动态SQL语句返回值
set recordcount = @recordcount;
以上我上再做存储过程分页里用到动态SQL里将查询到的count记录条数通过变量@recordcount放到recordcount里面了。
mysql的IF ELSE和其他数据库的判断有点不一样，简单的判断语句如下。
代码如下:
#根据总记录跳数计算出总页数  
set pagecount = ceiling((recordcount+0.0)/pagesize);  
if pageindex <1 then 
    set pageindex = 1;  
elseif pageindex > pagecount then 
    set pageindex = pagecount;  
else 
    select pageindex,pagecount;  
end if; 

#根据总记录跳数计算出总页数 set pagecount = ceiling((recordcount+0.0)/pagesize); if pageindex <1 then set pageindex = 1; elseif pageindex > pagecount then set pageindex = pagecount; else select pageindex,pagecount; end if;

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