Thank you very much Amit.
One more question in the same way if I want to join multiple tables
> select blah, blah
> From
> page_events pe
Left Join referrer ref
on ref.id = pe.id
> Left Join page_events pe_pre
> on pe.day = pe_pre.day
> And pe.session_id = pe_pre.session_id
> And pe.page_seq_num = pe_pre.page_seq_num + 1
Can we do this in one statement in Pig?
Thanks again for your help.
Sonia
On Wed, Feb 16, 2011 at 2:40 PM, Ramesh, Amit <[email protected]> wrote:
>
> You can just do:
>
> join_pe_pre = JOIN page_events BY (day, session_id, page_seq_num) LEFT
> OUTER, page_events_pre BY (day, session_id, page_seq_num + 1);
>
> Amit
>
>
> On 2/16/11 2:09 PM, "sonia gehlot" <[email protected]> wrote:
>
> > Hi All,
> >
> > I am new to Hadoop and I started exploring Pig since last month. I have
> few
> > question I have to replicate some SQL query to Pig that has left join for
> > example:
> >
> > select blah, blah
> > From
> > page_events pe
> > Left Join page_events pe_pre
> > on pe.day = pe_pre.day
> > And pe.session_id = pe_pre.session_id
> > And pe.page_seq_num = pe_pre.page_seq_num + 1
> >
> > So I wanted to confirm is this is the right and only way to do multi
> column
> > join in Pig? Or we can do this in some other way?
> >
> > join1_pe_pre = JOIN page_events BY day LEFT OUTER, page_events_pre BY
> day ;
> >
> > join2_pe_pre = JOIN join1_pe_pre BY session_id LEFT OUTER,
> page_events_pre
> > BY session_id ;
> >
> > join3_pe_pre = JOIN join2_pe_pre BY page_seq_num LEFT OUTER,
> page_events_pre
> > BY page_seq_num +1 ;
> >
> > Thanks for your help.
> >
> > Sonia
>
>
