Mysql - How do I display two values in the graph

I would like to display two series as for the graph below I would like to see the number hours the boiler has been on and the max temperature. The query below works in MySQL and returns both the heatstage and the outside temperature. Is it possible to show the two series, right now it will only show the heatstage.

UNIX_TIMESTAMP(DateCreated) as time_sec,
(sum(heatstagesec)*0.000277778), Max(OutdoorTemperature) as value,
‘Temperature’ as metric
FROM ecobee
WHERE $__timeFilter(DateCreated)
group by day(DateCreated)

I think you need two queries for time series as each query can only return one value column.

you might be able to do it with one query using a union query (and have different values in metric column)

you always the best, I will try, thanks for all your help.


Not that familiar with Union and my query is not working when I try to implement it. Do you remember by any chance someone with similar problem and solution?