Invalid aggregate reference

You'll get this error when you try to reference an aggregate from WHERE clause. For example:

select id, max(change_date)
from t1
where max(change_date) > current_timestamp
group by id;

You need to reference the aggregates in HAVING clause:

select id, max(change_date)
from t1
group by id
having max(change_date) > current_timestamp;

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