Grouping multiple rows on a condition using while loop

Question

In MySQL I have a table that looks like this: This is a little complex as mysql doesnot support ranking window functions and it does not even support CTEs so I'm trying to implement it using while loop

If there is any relationship between the imported and section then they should be grouped together. Depending on the relationship they should be grouped as 1,2,3,4,....

But in this scenario my rn is always 1 and not sure why its not incrementing. Can you help me review this query? I'm not sure how to go around this.

Example creation script:

    create table temp1 (
    id int, imported int, section int, rn int, checked int default 0
    );
    insert into temp1(id, section, rn)           values (204, 718, 0);
    insert into temp1(id, imported, section, rn) values (997,718,034,0);
    insert into temp1(id, imported, section, rn) values (998,034,055,0);
    insert into temp1(id, imported, section, rn) values (111,453,234,0);
    insert into temp1(id, section, rn) values (908, 453,0);
    insert into temp1(id, imported, section, rn) values (231,234,890,0);
    insert into temp1(id, section, rn) values (342, 567,0);

My End Result should look like:

I'have tried with while loop too creating a stored procedure:

    DROP PROCEDURE IF EXISTS sp_recursiveimport;
    Delimiter $$
    CREATE PROCEDURE sp_recursiveimport()  -- (IN rnX integer)
    BEGIN
    DECLARE n INT DEFAULT 0;   DECLARE i,j,k INT DEFAULT 0;    SELECT COUNT(*) FROM temp1 INTO n;
    SET i=0; set @rn = 1; --  set @k = 0;
    WHILE i<n DO 
    set j = 0; select i;
      set @sec = (select ifnull(section,0) FROM temp1 LIMIT i,1);          
      set @imp = (select ifnull(imported,0) FROM temp1 LIMIT i,1); select @imp, @sec;
        update1: while j<n do   select j;
    --         if j=0 then
               if (select ifnull(imported,0) from temp1 limit j,1) = @sec and (select checked from temp1 limit j,1) = 0 then 
               set @update  = concat('update temp1 set rn = 1, checked = 1 where imported = ',@sec); select @update;    PREPARE stmt_name FROM @update;     EXECUTE Stmt_name;     DEALLOCATE prepare stmt_name;
               set @update1 = concat('update temp1 set rn = 1, checked = 1 where section = ',@sec); select @update1;   PREPARE stmt_name FROM @update1;     EXECUTE Stmt_name;     DEALLOCATE prepare stmt_name;
               set k = j;
               end if;
               if (select ifnull(section,0)          from temp1 limit j,1) = @imp and (select checked from temp1 limit j,1) = 0 then 
               set @update3 = concat('update temp1 set rn = 1, checked = 1 where section = ',@imp);  select @update3;    PREPARE stmt_name FROM @update3;     EXECUTE Stmt_name;     DEALLOCATE prepare stmt_name;
               set @update4 = concat('update temp1 set rn = 1, checked = 1 where imported = ',@imp); select @update4;    PREPARE stmt_name FROM @update4;     EXECUTE Stmt_name;     DEALLOCATE prepare stmt_name;
               set k = j;
               end if;

    --            set @sec = (select ifnull(imported,0) from temp1 limit k,1);
    --            set @imp = (select ifnull(section,0)          from temp1 limit k,1); select @sec, @imp;
        set j= j+1;
        end while update1;

      set i = i + 1;
    END WHILE;
    END;
    $$
    delimiter;

Not sure why its not working.