Union streams

[lpf4254302]

What would you like to be added/modified:
Multi Topic Source
{"sql":"create stream lpf_stream () WITH ( datasource = "topic/t1,topic/t2,topic/t3", FORMAT = "json", TYPE="mqtt")"}
or
{
"id": "multi1",
"name": "multi1",
"graph": {
"nodes": {
"device1": {
"type": "source",
"nodeType": "httppush",
"props": {
"datasource": "/iot/alarm1"
}
},
"device2": {
"type": "source",
"nodeType": "httppush",
"props": {
"datasource": "/iot/alarm2"
}
},
"humidityFilter": {
"type": "operator",
"nodeType": "filter",
"props": {
"expr": "humidity > 30"
}
},
"logout1": {
"type": "sink",
"nodeType": "log"
}
},
"topo": {
"sources": [
"device1", "device2"
],
"edges": {
"device1": ["humidityFilter"],
"device2": ["humidityFilter"],
"humidityFilter": ["logout1"]
}
}
}
}
Why is this needed:
Wildcard mode allows you to subscribe to multiple topics, but sometimes multiple topics cannot be represented by wildcards

[ngjaying]

Thank you for bringing this up. A general "merge" node may be needed to merge not only different topics of the same source but also any type of data sources into one. It is not a problem in graph API. Any idea if SQL has such similar syntax?

[lpf4254302]

Thank you for bringing this up. A general "merge" node may be needed to merge not only different topics of the same source but also any type of data sources into one. It is not a problem in graph API. Any idea if SQL has such similar syntax?

sql:
(select * from root.sg1.t1) union all (select * from root.sg1.t2)
or
select * from root.sg1.t1,root.sg1.t2

[wfnuser]

I'd like to have a try on this issue. Can you assign it to me. 😊 @ngjaying