Performing ETL on a dataset, I have obtained the "yyyyMM" column as "MonthYear", and total "CB" in that month.
Now, I want to find out total CB of previous 3 months, for each month.
In SQL, I can do that by a nested subquery, or using self-join. How do I execute this query on the current Talend job without having to store the rows as a table in a (MySQL) DB?
My other option is to use Talend components to carry out the remaining steps.
But are there any components in Talend where I can extract rows iteratively and perform aggregation on them? Or some way to perform join and aggregation both in tMap?
I have attempted this so far ... but how do I get the "test" expression to be evaluated iteratively?
Amy you can try tHashoutput. First load derived data in tHasoutput and use that as source usingtHashInput and do you required calculations.
Watch the recorded webinar!
Create systems and workflow to manage clean data ingestion and data transformation.
Introduction to Talend Open Studio for Data Integration.
Test drive Talend's enterprise products.