To use the MEDIAN Function
MEDIAN(TagTag1,TagTag2,Tag)Tag3)
The median is the value separating the higher half of a data sample, a population, or a probability distribution, from the lower half. For a data set, it may be thought of as the "middle" value.
Advantage of the median in describing data compared to the mean is that it is not skewed so much by extremely large or small values, and so it may give a better idea of a "typical" value
Tag1 < Tag2 < Tag3 Output is Tag2
MEDIAN(Demo-influxdb/DEMO_01TI031.PV,Demo-influxdb/DEMO_01TI032.PV,Demo-influxdb/DEMO_01TI021.PV)