Question

I have a form to edit mysql table columns. There are links that I can click onto and load Previous, Next, First or Last row. I can order the columns (max. four columns to be ordered). So when I press Prev. or Next, the columns have to be ordered first and then I can get the result. I use mysql View for this. It is important to know that columns are text, but id is number. I usually order by first text columns and then by id.

And here is my query that worked to me for single column order.

Previous:

  SELECT  x.* 
    FROM  test_view x, test_view y 
   WHERE   y.`id` = 13 
           AND ( x.`cat` < y.`cat` OR ( x.`cat` = y.`cat` AND x.`id` < y.`id`)) 
ORDER BY  x.`cat`, x.`id` DESC   
   LIMIT  0,1

Next:

  SELECT  x.* 
    FROM  test_view x, test_view y 
   WHERE  y.`id` = 13 
          AND (x.`cat` > y.`cat` OR (x.`cat` = y.`cat` AND x.`id` > y.`id`)) 
ORDER BY  x.`cat`, x.`id` ASC   
   LIMIT  0,1

I tried to expand this to find multiple columns as this:

SELECT x . *
FROM ukazka_view x, ukazka_view y
WHERE y.`id` =1
AND (
x.`cat` < y.`cat`
OR (
x.`cat` = y.`cat`
AND x.`id` < y.`id`
)
)
AND (
x.`typ` < y.`typ`
OR (
x.`typ` = y.`typ`
AND x.`id` < y.`id`
)
)
AND (
x.`diff` < y.`diff`
OR (
x.`diff` = y.`diff`
AND x.`id` < y.`id`
)
)
ORDER BY x.`cat` DESC , x.`typ` DESC , x.`diff` DESC , x.`id` DESC
LIMIT 0 , 1

But this has no results.

Edited:

I tried to write a query for case that actual row id is 1.

    SELECT x.* FROM  ukazka_view x INNER JOIN ukazka_view y ON  
( x.`cat` < y.`cat` OR 
( x.`cat` = y.`cat` AND x.`id` < y.`id`) OR
( x.`cat` = y.`cat` AND y.`id` = 1 AND x.`id` > y.`id`))

AND
( x.typ < y.typ OR
( x.typ = y.typ AND x.id < y.id) OR
( x.typ = y.typ AND y.id = 1 AND x.id > y.id))
AND
( x.diff < y.diff OR
( x.diff = y.diff AND x.id < y.id) OR
( x.diff = y.diff AND y.id = 1 AND x.id > y.id))
WHERE y.id = 1
ORDER BY x.cat DESC, x.typ DESC, x.diff DESC, x.id DESC LIMIT 0,1

This looks for previous row. Behavior is a little bit strange but works. So when I go to last value, I got id=1. Then When I press Previous (this query) it gets to id=82, when I press again Previous id=81 and so on till I got id=2. I cannot get to id=1 only when I press/select Last.

Answer 1

SELECT x.*
FROM ukazka_view x
INNER JOIN ukazka_view y 
  ON  (x.cat  < y.cat  OR (x.cat  = y.cat  AND x.id < y.id)) 
  AND (x.typ  < y.typ  OR (x.typ  = y.typ  AND x.id < y.id))  
  AND (x.diff < y.diff OR (x.diff = y.diff AND x.id < y.id))
WHERE y.id = 1
ORDER BY x.cat DESC , x.typ DESC , x.diff DESC , x.id DESC
LIMIT 1 OFFSET 0

The problem I see with this query is that an id cannot be smaller than 1.
So x.id < y.id will always be false.
This leaves only

....
  ON  (x.cat  < y.cat)
  AND (x.typ  < y.typ)
  AND (x.diff < y.diff)

As a join criterion.