Ning, Thanks for the reply.
Yes. you are right. Using NOT and AND didn't work as expected.
I'll give a try in implementing nested-loop map-side join.
In the meanwhile, I brought out the expression using OR from inside the JOIN
expression to be used in the filtering expression {in the WHERE clause
Here is my query :*
select table1.column10, table1.column11, count(distinct table2.column3) as
total from table1 JOIN table2 ON (table1.column1='value1' and
to_date(table1.column2) = '2011-01-06' and to_date(table1.column2)
'2011-01-07' and table2.column3!='' and table2.column3 is NOT NULL and
I want to use OR in the join expression, but it seems only AND is supported
as of now.
I have a work around though to use DeMorgan's law {C1 OR C2 = !(!C1 AND
!C2))} , but it would be nice if somebody can point me to the location in
code base that would need modification to support the OR in the
Found it at *org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.java* line
no. 1122
There is some concern mentioned that supporting OR would lead to data
explosion. Is it discussed/documneted in a little more detail somewhere ? If
so, some pointers towards the same will be helpful.
Thanks,
MIS.
Joins with OR conditions are not supported by Hive currently. I think even
though you rewrite the condition to use NOT and AND only, the results may be
wrong.
It is quite hard to implement joins of any tables with OR conditions in a
MapReduce framework. it is straightforward to implement it
