Hi Swapna, All our aggregate functions allow expressions as arguments and it wouldn't make sense to have these new ones be different. A reference to a column is also an expression. It doesn't change the HBase data model being sparse.
I think the next step should be for you to submit a patch that the community can take a look at, as it's too difficult to discuss this without that. Thanks, James On Tuesday, May 3, 2016, Swapna Swapna <[email protected]> wrote: > Hi James, > > Thanks for your swift response. > > I wouldn't be able to use the expression in the below query rather I would > have to provide the columns (as arguments) which I'm interested in to > perform the aggregation on respective provided columns. > > myaggFunc(col1,col2) > > the reason being, the hbase data is sparsed and I would not know the column > values. Data fetch is based on a row key. > > expression example: > > ID=1 OR NAME='Hi' > > Regards > > Swapna > > > > On Tue, May 3, 2016 at 7:17 PM, James Taylor <[email protected] > <javascript:;>> wrote: > > > Hi Swapna, > > The return type is typically derived from looking at the return types of > > each of the input arguments and choosing what'll work without losing > > precision. For example, take a look at this loop in ExpressionCompiler > that > > determines this for expressions that are added together: > > > > new ArithmeticExpressionFactory() { > > @Override > > public Expression create(ArithmeticParseNode node, > > List<Expression> children) throws SQLException { > > boolean foundDate = false; > > Determinism determinism = Determinism.ALWAYS; > > PDataType theType = null; > > for(int i = 0; i < children.size(); i++) { > > > > Your probably already doing this, but make sure you don't assume the > > arguments are column references, but allow them to be any expression. > > > > Also, it'd be great to see what you've got so far without handling > multiple > > arguments to your function (in the form of a pull request) so folks can > get > > you feedback on your work so far. > > > > Thanks, and we appreciate the contributions! > > > > James > > > > On Tue, May 3, 2016 at 12:59 PM, Swapna Swapna <[email protected] > <javascript:;>> > > wrote: > > > > > Sure, > > > > > > Hbase data that I have is: > > > > > > rowkey us uk > > > 20161001 3 4 > > > 20161002 1 2 > > > > > > > > > select myaggFunc(us) from table : // this is returning output as : > > > 4 > > > select myaggFunc(uk) from table : // this is returning output as : > > > 6 > > > > > > In similar to that, i'm visualizing the query like: select > > > myaggFunc1(us,uk) > > > from table; //with multiple columns > > > > > > to return output: (based on the aggregation logic, below results are > > for > > > sum aggregation) > > > us 4 > > > uk 6 > > > > > > > > > > > > On Tue, May 3, 2016 at 11:33 AM, James Taylor <[email protected] > <javascript:;>> > > > wrote: > > > > > > > Removing user list (please don't cross post) > > > > > > > > Can you give us a full example of the query you have in mind? > > > > > > > > Thanks, > > > > James > > > > > > > > On Tue, May 3, 2016 at 11:14 AM, Swapna Swapna < > [email protected] <javascript:;> > > > > > > > wrote: > > > > > > > > > Hi, > > > > > > > > > > I'm trying to implement aggregate function on multiple columns (as > an > > > > > arguments) like: > > > > > > > > > > myaggFunc(col1,col2) > > > > > > > > > > And I would want to return the results by each column after > applying > > > > > aggregate operation. > > > > > > > > > > The output would be something like: > > > > > > > > > > col1, count ( aggregate of all records for col1) > > > > > col2, count > > > > > > > > > > Inorder to return the results in the above format, what is the > return > > > > data > > > > > type (of the method) should I have to choose? > > > > > > > > > > Thanks > > > > > > > > > > > > > > >
