Re: [HACKERS] OLAP, Aggregates, and order of operations
mlw <[EMAIL PROTECTED]> writes: > I need to do some OLAP stuff, and I asked previously if there were a way > to pass multiple parameters to an aggrigate function. i.e.: > I looked through the code and it is non-trivial to do, Offhand I don't know of any fundamental reason why it couldn't be done, but you're right that it'd take a fair amount of work. > If I do this: > select mycube(value1) as d1, dimention(value2) as d2, dimention(value3) > as d3 group by value1; > Can I safely assume the following: > (1) mycube() will be called first > (2) Assuming dimention() has no final func, that final func of mycube() > will be called last. That might be true in the present code, but it strikes me as an awfully risky set of assumptions. Also, it sounds like what you have in mind is to have some hidden state that all the aggregate functions will access; how then will you work if there are more than one set of these aggregates being used in a query? If the needed parameters are all the same datatype, maybe you could put them into an array and pass the array as a single argument to the aggregate. regards, tom lane ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
[HACKERS] OLAP, Aggregates, and order of operations
I need to do some OLAP stuff, and I asked previously if there were a way to pass multiple parameters to an aggrigate function. i.e.: select mycube(value1, value2, value3) from table group by value1; I looked through the code and it is non-trivial to do, one would have to alter the grammar to include a number of parameters, I guess something like this: create aggregate (sfunc = myfunct, sfuncnargs=3, stype = int4, basetype1 = int4, basetype2 = int4, ); Then change the catalog, and the execution, arrg! (God I wish I could spend the time I want on PostgreSQL! ) Anyway, short of that If I do this: select mycube(value1) as d1, dimention(value2) as d2, dimention(value3) as d3 group by value1; Can I safely assume the following: (1) mycube() will be called first (2) Assuming dimention() has no final func, that final func of mycube() will be called last. ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
