CODEWITHSUNDEEP
apache-flink
Tom
Tom

Reputation: 6342

How to join two streams with more than one join key

The following code snippet is copied from javadoc of JoinedStreams

val one: DataStream[(String, Int)]  = ...
val two: DataStream[(String, Int)] = ...

val result = one.join(two)
    .where {t => ... }
    .equal {t => ... }
    .window(TumblingEventTimeWindows.of(Time.of(5, TimeUnit.SECONDS)))
    .apply(new MyJoinFunction())

The two streams are joined based on only one key (computed through t => ...), eg, one.a = two.a,

I would ask how I could do the join based on more than one key, eg, one.a = two.a and one.b = two.b

Upvotes: 0

Views: 189

Answers (2)

David Anderson
David Anderson

Reputation: 43707

Your key selectors can return a Tuple, i.e.,

.where {t => (t.a, t.b)}
.equals {t => (t.a, t.b)}

Upvotes: 1

Jiayi Liao
Jiayi Liao

Reputation: 1009

By using KeySelector when join, you can generate a tuple to present two keys.

Upvotes: 1

Related Questions