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Davide Giannella commented on OAK-4265: --------------------------------------- Can we leverage the optimisation hook we provided with OAK-1617 for generating alternatives that will be considered then by costs? > XPath: support limited form of "union" > -------------------------------------- > > Key: OAK-4265 > URL: https://issues.apache.org/jira/browse/OAK-4265 > Project: Jackrabbit Oak > Issue Type: New Feature > Components: query > Reporter: Thomas Mueller > Assignee: Thomas Mueller > Fix For: 1.6 > > > Currently, SQL-2 supports multiple paths restrictions combined with "or", and > it supports "union". XPath doesn't support either. It would be good if this > is supported, specially the "multiple paths" part. > I think it makes sense to convert this to a SQL-2 "union" in all cases, even > if it's just multiple paths. > It doesn't need to be a "generic" solution, so that "|" doesn't need to be > supported at every place (for example in the condition, or in the "order > by"). But it would be nice if multiple independent queries, with one order > by, could be supported. > Implementation note: what makes this a bit complicated is support for "order > by". > For example: > {noformat} > /jcr:root/(content|lib)/element(*, nt:base) order by @title > select [jcr:path], [jcr:score], * > from [nt:base] as a > where ischildnode(a, '/content') > /* xpath: /jcr:root/content/element(*, nt:base) order by @title */ > union select [jcr:path], [jcr:score], * > from [nt:base] as a > where ischildnode(a, '/lib') > /* xpath: /jcr:root/lib/element(*, nt:base) order by @title */ > order by [title] > {noformat} -- This message was sent by Atlassian JIRA (v6.3.4#6332)