Subqueries in where clause failing

[severingaudet]

select O.collection, O.observationID, O.maxLastModified         
from caom2.Observation as O left outer join caom2.Plane as P on O.obsID = P.obsID
where O.collection = 'POSSUM' and P.planeID is null

fails in Topcat with the following message:

        select O.collection, O.observationID, P.planeID, P.dataProductType, P.maxLastModified
        from caom2.Observation as O join caom2.Plane as P on O.obsID = P.obsID
        where collection = '{collection}' and (quality_flag is null or quality_flag != 'junk')
        and exists (select NULL from caom2.Artifact as A where P.planeID = A.planeID and A.productType = 'science')
        and exists (select NULL from caom2.Artifact as A where P.planeID = A.planeID and A.productType = 'preview')
        and exists (select NULL from caom2.Artifact as A where P.planeID = A.planeID and A.productType = 'thumbnail')

[pdowler]

the alias in the outer query is not visible in the subquery...

that sql works in the database so that's a bug in the ADQL parser... when it parses/analyzes a subquery it does not have the context of the outer query (the from caom2.Observation as O so it can't resolve the alias O to a table)