Group By Support
I'm student in Computer Science at the Free University of Brussel (ULB).
For my end of studies work, i would like to add the keyword groupby to XQuery in order to evaluate the advantages of this addition for OLAP queries on a XML datawarehouse.
For example here a multiple groupby in Xquery :
This expression suggest several passes over all the data.
Its equivalent in sql :
I would like to implement something like that with eXist :
This last expression is easier to optimise and need less passes on the data.
PS : sorry for my poor english ;-)
- 0 Comments
- Add Comment