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javaleft-joinesper

Esper left outer join with subquery

I'm trying to apply in essper this query:

select a.partA, b.partB, b.count from call.win:time_batch(_WINDOW_) as a
left outer join (select count(*) count, partA from 
call.win:time_batch(_WINDOW_) group by partA ) b on a.partA = b.partA

but I got exception

Caused by: com.espertech.esper.client.EPStatementSyntaxException: Incorrect syntax near '(' ('select' is a reserved keyword) at line 1 column 96, please check the outer join within the from clause near reserved keyword 'select' [select a.partA, b.partB, b.count from call.win:time_batch(WINDOW) as a left outer join(select count(*) count, partA from call.win:time_batch(WINDOW) group by partA ) b on a.partA = b.partA]

call is my eventTypeName

Solution

  • As far as I know there is no support for subqueries in the from-clause in Esper as of version 5.4.