SQL query gets stuck if adding ORDER BY-CodePudding

I am working with a query, which looks like this

SELECT s.c1, s.t, s.u, s.dt, t.temp, t.dt AS dt2
FROM `systemusage` AS s
    INNER JOIN temperature AS t ON s.did=t.did
WHERE t.did = (SELECT id FROM devices WHERE m = 1)
LIMIT 1

Which works just fine, however if I add ORDER BY s.id, then the query gets totally stuck, can someone guide me on why? the id field is primary, so it should be indexed no?

CodePudding user response：

Add an index on the column temperature.did so that the WHERE clause can be implemented efficiently.