10-12-2016 03:34 AM - edited 10-12-2016 03:45 AM
Is it possible to define aggregated measures in computed columns using proc imstat?
I did not find a lot of documentation on computed columns in proc imstat. Following paper did supply a bit of info:
COMPUTED COLUMNS Using computed columns at data load time offers a couple of key advantages. First, computed columns are virtual and exist as code that executes when the table is accessed. In effect, this does not increase your data footprint in HDFS or in the data warehouse. Second, using computed columns in this way may provide you more flexibility in changing the calculation(s) if and when business rules change. Use PROC IMSTAT to add a permanent computed column to an in-memory table:
compute computed1 "computed1=mpg_city/mpg_highway";
It is worth noting that adding calculated columns at load time presents all users with the same calculation and report designers do not need to calculate the measures for every report.
10-13-2016 05:05 PM
Row-wise operations can be performed, similar to the ratio example that you showed.
compute sum1 "sum1=sum(mpg_city, mpg_highway)";
compute weird1 "weird1=min(weight, (enginesize * cylinders * horsepower * 2));";