Can you have optional measurements with max_by()?
Can you do a max_by() and not throw an error if the column doesn't exist?
select customer, site, system, max(time),
max_by("loads", time) as loads,
max_by("weight", time) as lbs,
max_by("turns", time) as turns
from "x"."x-test"
where time > ago(12h)
AND customer='TEST'
AND site='TEST'
AND system='TEST'
AND measure_name = 'system-status'
GROUP BY customer, site, system
The probably really is that I want to return max_by("*", time) but that's not possible. The problem is that max_by() won't return null if the column doesn't exist; it will just throw an exception.
I am working off of this doc section 1 (last value queries) as my template. I can use the first example (WITH ... SELECT ...) but as the document points out this is more expensive. It'd be better to use max_by() but not have it flip out of 'weight' or 'turns' is not in that particular MULTI record.
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Hello,
In Timestream, before executing a query it verifies that all the columns specified in the query actually exists in the corresponding tables. If not, the database will return a “column does not exist error.” Timestream will not assume an empty/null value for a non-existent column. So in this case you would have to pass an existing column in max_by() function. Please let us know if you have more questions.
