Hi Yifei, if you don't wanna implement your own join operator, then you could also chain two join operations. I created a small example to demonstrate that: https://gist.github.com/tillrohrmann/c074b4eedb9deaf9c8ca2a5e124800f3. However, bare in mind that for this approach you will construct two windows which might be a bit more costly than Aljoscha's approach.
Cheers, Till On Tue, Apr 19, 2016 at 11:32 AM, Aljoscha Krettek <aljos...@apache.org> wrote: > Hi, > right now, there is no built-in support for n-ary joins. I am working on > this, however. > > For now you can simulate n-ary joins by using a tagged union and doing the > join yourself in a WindowFunction. I created a small example that > demonstrates this: > https://gist.github.com/aljoscha/a2a213d90c7c1bc67e71fabaa82fba4a > > I hope this helps, and please let us know if you want to know more. > > Cheers, > Aljoscha > > On Tue, 19 Apr 2016 at 02:11 Yifei Li <lee891...@gmail.com> wrote: > >> Hi, >> >> I am new to Flink and I've read some documentation and think Flink may >> fit my scenario. >> >> Here is my scenario: >> >> 1. Assume I have 3 streams: S1(id, name, email, action, date), S2(id, >> name, email, level, date), S3(id, name, position, date). >> >> *2. S2 always delays(hours to days, not determined..) * >> >> 3. Based on the event time, I want to join S1, S2 and S3 every 5 minutes. >> The join is like a SQL join: >> select S1.name, S3.position from S1, S2, S3 where S1.id = S2.id and >> S1.id = S3.id and S1.action = 'download' and S2.level = 5 >> >> >> >> Can I use Flink for my scenario? Is yes, can anyone point me to some >> working examples(I found some examples but they are outdated), or tell me >> some workaround to solve this problem? If no, can anyone tell me the >> reasons? >> >> Thanks, >> >> Yifei >> >> >> >> >> >>
