MYSQL, PHP, order by not working, primary key - mysql

Question

I am generating a mySQL query from PHP.
Part of the query re-orders a table based on some variables (which do not include the primary key).
The code doesn't produce errors, however the table is not sorted.
I echo'd out the SQL code, and it looks correct, I tried running it directly in phpMyAdmin, and it runs also without error, but the table is still not sorted as requested.
alter table anavar order by dset_name, var_id;
I am pretty sure that this has to do with the fact that I have a primary key variable (UID) which is not present in the sort.
Both prior and post running the query the table remains ordered by UID. Deleting UID and re-running the query results in a correctly sorted table, but this seems like an overkill solution.
Any suggestions?

Answer 1

create table t2
( id int auto_increment primary key,
someInt int not null,
thing varchar(100) not null,
theWhen datetime not null,
key(theWhen) -- creates an index on theWhen
);
-- my table now has 2 indexes on it
-- see it by running `show indexes from t2`
-- truncate table t2;
insert t2(someInt,thing,theWhen) values
(17,'chopstick','2016-05-08 13:00:00'),
(14,'alligator','2016-05-01'),
(11,'snail','2016-07-08 19:00:00');
select * from t2; -- returns in physical order (the primary key `id`)
select * from t2 order by thing; -- returns via thing, which has no index anyway
select * from t2 order by theWhen,thing; -- partial index use
note that indexes aren't even used until you have a significant number of rows in a db anyway
Edit (new data comes in)
insert t2 (someInt,thing,theWhen) values (777,'apple',now());
select t2.id,t2.thing,t2.theWhen,#rnk:=#rnk+1 as rank
from t2
cross join (select #rnk:=0) xParams
order by thing;
+----+-----------+---------------------+------+
| id | thing | theWhen | rank |
+----+-----------+---------------------+------+
| 2 | alligator | 2016-05-01 00:00:00 | 1 |
| 4 | apple | 2016-09-04 15:04:50 | 2 |
| 1 | chopstick | 2016-05-08 13:00:00 | 3 |
| 3 | snail | 2016-07-08 19:00:00 | 4 |
+----+-----------+---------------------+------+
Focus on the fact that you can maintain your secondary indices and generate a rank on the fly whenever you want.