I see. I've noticed in past conversations that people generally deal with this by using a magic value instead of NULLs. Which works fine in simple cases like:
SELECT AVG(a) WHERE a != <magic> However, I am in a situation where I need the query to return multiple aggregations such as: SELECT AVG(a), AVG(b) WHERE 1 = 1 and I would like AVG(a) to average all non-magic values of 'a' and AVG(b) to average all non-magic values of 'b'. Any suggestions on now to go about doing this? Thanks, Michael On Thu, Nov 1, 2012 at 3:48 PM, K. John Wu <[email protected]> wrote: > Hi, Michael, > > The NULL values in CSV fiels are not ignored by ardea, but by the > query processing code. Basically, FastBit query results can not > contain NULLs, so 'SELECT a WHERE 1 = 1' will return three rows while > 'SELECT b WHERE 1 = 1' will only return two. > > John > > > On 11/1/12 1:55 PM, Michael Beauregard wrote: >> Hey John, >> >> I'm a bit confused as to how NULLs in csv files are treated by ardea. >> Here is an experiment I just did: >> >> in "nulls.csv": >> >> 10,1 >> 20, >> 30,3 >> >> then load the data with ardea: >> >> ardea -d tmp/nulls_test -m a:int,b:int -t nulls.csv >> >> then query with ibis: >> >> ibis.sh -d tmp/nulls_test -q 'SELECT a, b WHERE 1 = 1' -o out.txt >> >> cat out.txt >> 10, 1 >> 30, 3 >> >> For some reason the csv row with a NULL in it is ignored by ardea. >> This is unexpected for me, but I'm wondering if this is working as >> designed or not. If this is expected behaviour, then I'm wondering how >> I can specify NULL values when loading data. >> >> Thanks, >> >> Michael >> _______________________________________________ >> FastBit-users mailing list >> [email protected] >> https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users >> _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
