MySQL: having rounded sum not equal to integer - mysql

Question

I have a query in which I compare a rounded sum to an integer, and I'm receiving unexpected results.
SELECT assignments.*
FROM assignments
INNER JOIN time_entries
ON time_entries.assignment_id = assignments.id
WHERE assignments.organization_id = 2
AND assignments.allocation_mode = 'fixed'
AND (fixed_hours is not null)
HAVING round(sum(time_entries.scheduled_hours)) != round(assignments.fixed_hours);
It returns an assignment with fixed_hours of 20. The column is a float.
When I select the sum of the time_entries for that match that record, I get 20.000000298023224. When I call round on that, I get 20:
SELECT
round(sum(scheduled_hours))
FROM time_entries
WHERE assignment_id=112869;
And SELECT round(fixed_hours) from assignments where id=112869 also gives 20.
And of course select round(20.000000298023224) = round(20); returns 1.
So what's wrong with my query that that record is being returned?

Answer 1

Nice try at query summarization :), but you need a group by...
SELECT
assignments.*
FROM assignments
INNER JOIN (
SELECT
assignment_id
, ROUND(SUM(time_entries.scheduled_hours)) sum_hrs
FROM time_entries
GROUP BY
assignment_id
) te ON assignments.id = te.assignment_id
WHERE assignments.organization_id = 2
AND assignments.allocation_mode = 'fixed'
AND (fixed_hours IS NOT NULL)
AND te.sum_hrs <> ROUND(assignments.fixed_hours)
;