MySQL Update Sorted Number - mysql

Question

I have MYSQL data like this
id | number
1 | 3
4 | 4
7 | 7
10 | 5
11 | 6
I have the database like that, and how to update the number so it will be sorted incremental?
Which mean the result will be like this
id | number
1 | 1
4 | 2
7 | 3
10 | 4
11 | 5
i updated the question so there will be no confusion in id and since id will be not consecutive

Answer 1

set #val = 0;
update table_name set number = (#val:=#val+1);
This would work even if table is:
id | number
1 | 3
4 | 4
7 | NULL
10 | 5
11 | NULL
to be like this:
id | number
1 | 1
4 | 2
7 | 3
10 | 4
11 | 5

Answer 2

update table set number=id where 1

Answer 3

Try this:
SET #idrank = 0;
SET #numrank = 0;
UPDATE
tbl a
INNER JOIN
(
SELECT id, #idrank:=#idrank+1 AS id_rank
FROM tbl
ORDER BY id
) b ON a.id = b.id
INNER JOIN
(
SELECT number, #numrank:=#numrank+1 AS number_rank
FROM tbl
ORDER BY number
) c ON b.id_rank = c.number_rank
SET
a.number = c.number;
This will account for gaps and irregularities in the number field as well as duplicates. Say the entire data set was something like:
id | number
---------------
2 | 534
3 | 421
6 | 2038
7 | 41
10 | 5383
11 | 5
12 | 933
15 | 43
The resulting table set after the update will be:
id | number
---------------
2 | 5
3 | 41
6 | 43
7 | 421
10 | 534
11 | 933
12 | 2038
15 | 5383
Explanation:
It basically takes the ascending ranks of each field separately and joins on the ranks so that the ordered id is matched up with corresponding ordered number.
The first INNER JOIN subselect will look like this:
id | id_rank
---------------
2 | 1
3 | 2
6 | 3
7 | 4
10 | 5
11 | 6
12 | 7
15 | 8
Then the second INNER JOIN subselect will like this:
number | number_rank
---------------
534 | 5
421 | 4
2038 | 7
41 | 2
5383 | 8
5 | 1
933 | 6
43 | 3
Then when you join the two subselects on id_rank = number_rank, you line the ascending order of the two fields up. Once you have that, updating becomes a simple matter of setting the table's number = the second joined table's number.