create table products 
(id int not null primary key auto_increment,
 prodname  varchar( 40 ),
 position int default  200 );

insert into products set  prodname ='prod 1';
insert into products set  prodname ='prod 2';
insert into products set  prodname ='prod 3';
insert into products set  prodname ='prod 4';
insert into products set  prodname ='prod 5';
insert into products set  prodname ='prod 6';
insert into products set  prodname ='prod 7';
insert into products set  prodname ='prod 8';

update products set position =  100  where id< 4 ;
update products set position =  1  where id= 3 ;
update products set position =  101  where id= 1 ;

select * from products order by position,id;

+ ----+--------+----------+ 
| id |prodname| position |
+ ----+--------+----------+ 
|   3  | prod  3  |         1  |
|   2  | prod  2  |       100  |
|   4  | prod  4  |       100  |
|   1  | prod  1  |       101  |
|   5  | prod  5  |       200  |
|   6  | prod  6  |       200  |
|   7  | prod  7  |       200  |
|   8  | prod  8  |       200  |
+ ----+--------+----------+ 
 8  rows in set ( 0 . 00  sec)

select id,prodname, 1  as pos from products where id= 3 
union 
(select id,prodname, 2  as pos from products where id<> 1  and id<> 3  limit  0 , 2 )
union  
select id,prodname, 3  as pos from products where id= 1 
union 
(select id,prodname, 4  as pos from products where id<> 1  and id<> 3  limit  2 , 99999999999 )
order by pos,id;

+ ----+--------+-----+ 
| id |prodname| pos |
+ ----+--------+-----+ 
|   3  | prod  3  |    1  |
|   2  | prod  2  |    2  |
|   4  | prod  4  |    2  |
|   1  | prod  1  |    3  |
|   5  | prod  5  |    4  |
|   6  | prod  6  |    4  |
|   7  | prod  7  |    4  |
|   8  | prod  8  |    4  |
+ ----+--------+-----+ 
 8  rows in set ( 0 . 00  sec)

(select id,prodname,price, 1  as pos from products where id=@ID_FIRST)
union
(select id,prodname,price, 2  as pos from products where id<>@ID_FIRST and id<>@ID_OTHER order by @FIELD_SORT imit @N- 2 )
union
(select id,prodname,price, 3  as pos from products where id=@ID_OTHER)
union
(select id,prodname,price, 4  as pos from products where id<>@ID_FIRST and id<>@ID_OTHER order by @FIELD_SORT limit @N- 2 , 99999999999 )
order by pos;