MySQL Order By alternate values

Question

Im having trouble in MySQL query Order By.

First I have a table(tbl_records) that contains 10000+ records. This table has a primary key called rec_id and a foreign key rec_f_id .

rec_f_id has only two kinds of value (555, 666).

Now my problem is how can I gather the records on the table that orders in alternate value of rec_f_id .

Eg

Below is a dummy tbl records

 | rec_id   |   rec_f_id |
 |2         |666         |
 |3         |555         |
 |7         |555         |
 |8         |666         |
 |9         |555         |
 |12        |666         |
 |25        |555         |
 |31        |555         |
 |84        |666         |
 |89        |555         |
 |91        |555         |
 |92        |666         |
 |113       |666         |
 |118       |666         |
 |125       |555         |
 |132       |555         |
 |170       |555         |
 |184       |666         |


 SELECT * FROM tbl_records ORDER BY FIELD(rec_f_id, 555, 666) LIMIT 100;

The above query only returns record with rec_f_id = 555. What I want to have is

 | rec_id   |   rec_f_id |
 |31        |555         |
 |12        |666         |
 |3         |555         |
 |8         |666         |
 |25        |555         |
 |2         |666         |
 |7         |555         |
 |84        |666         |
 |9         |555         |

 ...

Thanks!

Answer 1

try:

SELECT * FROM tbl_records
WHERE rec_f_id in (555,666) 
ORDER BY rec_id, rec_f_id,
LIMIT 100;

Answer 2

Here's one option using user-defined variables . Basically it creates a Row Number per Group, and then orders by it along with the rec_f_id field:

SELECT rec_id, rec_f_id
FROM (
  SELECT rec_id, rec_f_id,
    @rn:=IF(@prev=rec_f_id,@rn+1,1) rn,
    @prev:=rec_f_id
  FROM tbl_records
    JOIN (SELECT @rn:=0, @prev:=0) t
  ORDER BY rec_f_id
  ) t
ORDER BY rn, rec_f_id

• Sample SQL Fiddle