Hi, Yes, sure. Just use CEP on top of KeyedStream. Take a look at `keyBy`:
https://ci.apache.org/projects/flink/flink-docs-release-1.6/dev/stream/operators/ Piotrek > On 23 Nov 2018, at 16:04, Spico Florin <spicoflo...@gmail.com> wrote: > > Hello! > > I'm using Flink 1.4.2 and I would like to use a group by operator based on > value of my event stream. The functionality that I would like to achieve is > similar to the following Esper EPL > (excerpt > http://esper.espertech.com/release-5.2.0/esper-reference/html/epl_clauses.html#epl-grouping-aggregating > > <http://esper.espertech.com/release-5.2.0/esper-reference/html/epl_clauses.html#epl-grouping-aggregating>) > > > select symbol, tickDataFeed, median(volume) > from StockTickEvent.win:time(30 sec) > group by symbol, tickDataFeed > <> > > So, does the Flick CEP support such a group by functionality? > > If yes what is syntax? > > > > I look forward for your answers. > > > > Best regards, > > Florin > > > > > > (excerpt > http://esper.espertech.com/release-5.2.0/esper-reference/html/epl_clauses.html#epl-grouping-aggregating > > <http://esper.espertech.com/release-5.2.0/esper-reference/html/epl_clauses.html#epl-grouping-aggregating>) > "You can list more then one expression in the group by clause to nest groups. > Once the sets are established with group by the aggregation functions are > applied. This statement posts the median volume for all stock tick events in > the last 30 seconds per symbol and tick data feed. Esper posts one event for > each group to statement listeners: > In the statement above the event properties in the select list (symbol, > tickDataFeed) are also listed in the group by clause. The statement thus > follows the SQL standard which prescribes that non-aggregated event > properties in the select list must match the group by columns." >
