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From "Michael McCandless (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-7404) prepared query for introducing evaluation expression in query (not fixed second comparation member)
Date Fri, 05 Aug 2016 16:03:20 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-7404?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15409624#comment-15409624
] 

Michael McCandless commented on LUCENE-7404:
--------------------------------------------

Can't you use the expressions module with function queries to get close to this?

> prepared query for introducing evaluation expression in query (not fixed second comparation
member)  
> -----------------------------------------------------------------------------------------------------
>
>                 Key: LUCENE-7404
>                 URL: https://issues.apache.org/jira/browse/LUCENE-7404
>             Project: Lucene - Core
>          Issue Type: Improvement
>            Reporter: Cristian Lorenzetto
>
> Lucene is very powerfull but has a limitation very important. It is impossible to use
when you want create a query where is a expression inside. 
> field1: >= field2  where field1 and field2 is not possible.
> field1:= field2^2 -4 *field3 
> it is pratically impossible to index statically document for this query but it is possible
to do 2 things:
> 1) create a third field hidden here is saved the result.
> 2) when you use a prepared query , it is saved automatically in a different writer this
info that you can save. 
> Creating a prepared query lucene do all automatically for making this query using indexes.

> PS. Pay attention that fields in expression could be not only inside the current document
but also in different documents/readers.
> It could be used also for join different document types(it is a subcase of the above
problem).



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