#1221 - Incorrect usage of UPDATE and ORDER BY - mysql

Question

To bypass a problem I posted in a other thread. I tried an sql statement like this:
UPDATE user u JOIN (SELECT #i := 0) r
SET user_rank_planets = (#i := (#i + 1))
WHERE user_active=1
ORDER BY user_planets DESC
I got Error #1221. Without the order by clause, the statement works fine.
Is there someone who knows a solution for this issue?

Answer 1

You cannot use order by and limit in update statement in the case of multiple tables.
Quoting From MySQL Documentation:
For the multiple-table syntax, UPDATE updates rows in each table named
in table_references that satisfy the conditions. Each matching row is
updated once, even if it matches the conditions multiple times. For
multiple-table syntax, ORDER BY and LIMIT cannot be used.
UPDATE user u
INNER JOIN
(
SELECT
*,
(#i := (#i + 1)) AS row_number
FROM user u
CROSS JOIN (SELECT #i := 0) r
WHERE user_active=1
ORDER BY user_planets DESC
)AS t
ON u.Primary_key = t.primary_key
SET u.user_rank_planets = t.row_number.
Note: Replace u.Primary_key and t.primary_key by the primary key of user table.
Read first few paragraphs http://dev.mysql.com/doc/refman/5.7/en/update.html

Answer 2

The #1000111's answer doesn't work. I don't know the reason but MySQL just ignored the ORDER BY in the subquery and updated with the default order (by the Primary_key).
A silly solution is wrapping the subquery inside another subquery to create a temporary table.
UPDATE user u
INNER JOIN
(
SELECT * FROM (
SELECT *, (#i := (#i + 1)) AS row_number
FROM user u
CROSS JOIN (SELECT #i := 0) r
WHERE user_active=1
ORDER BY user_planets DESC
) AS t1
) AS t
ON u.<Primary_key> = t.<Primary_key>
SET u.user_rank_planets = t.row_number