Question

How can I select next and previous rows for a total of six rows in a query but with conditions:

I’ll always have 6 rows, so if i have:

1, 2, 3, 4, 5, 6, 7, 8, 9

and my ID is 2 the result must be:

1,3,4,5,6,7

if my ID is 5 the result must be:

2,3,4,6,7,8

if my ID is 9 the result must be:

3,4,5,6,7,8

edit:

(SELECT * FROM articulos 
      WHERE categoria = 'Y'
      AND numero >= 
       (SELECT IF(
          (SELECT COUNT(*) FROM articulos WHERE numero < X AND categoria = 'Y')<3,
          (SELECT MIN(X) FROM articulos WHERE categoria = 'Y'),
          (X-3)
       ))
      ORDER by numero ASC LIMIT 6)
UNION
(SELECT * FROM articulos 
      WHERE categoria = 'Y'
      AND numero <= 
       (SELECT IF(
          (SELECT COUNT(*) FROM articulos WHERE numero > 1605 AND categoria = 'Y')<3,
          (SELECT MAX(X) FROM articulos WHERE categoria = 'Y'),
          (X+3)
       ))
      ORDER by numero DESC LIMIT 6)

maybe this is the solution

Answer 1

Something like this:

 SELECT data
 FROM table
 JOIN ( SELECT 
    CASE 
       WHEN n > MAX(id)-3 THEN MAX(id) - 7
       WHEN n < 4 THEN 0
       ELSE n - 4 
    END AS lower_bound,
    CASE 
       WHEN n > MAX(id)-3 THEN MAX(id) + 1
       WHEN n < 4 THEN 7
       ELSE n + 4 
    END AS upper_bound
    FROM table ) AS t1
 WHERE id BETWEEN t1.lower_bound AND t1.upper_bound
 AND id <> n

should always select 6 rows

More info on the CASE function in the docs