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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (METAMODEL-200) No syntax available in SQL representation of Query for "function approximation"
Date Fri, 23 Oct 2015 12:26:27 GMT

    [ https://issues.apache.org/jira/browse/METAMODEL-200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14970896#comment-14970896
] 

ASF GitHub Bot commented on METAMODEL-200:
------------------------------------------

Github user LosD commented on the pull request:

    https://github.com/apache/metamodel/pull/62#issuecomment-150558274
  
    Code looks good, but it's not a particular good change to me: It is totally fine to add
new functions (like approximate_count() or something like that) that are not base SQL, but
breaking SQL syntax seems a bit... Nasty to me.
    
    Relational database vendors do all kinds of horrible things to SQL, but I don't think
even they would go that far.


> No syntax available in SQL representation of Query for "function approximation"
> -------------------------------------------------------------------------------
>
>                 Key: METAMODEL-200
>                 URL: https://issues.apache.org/jira/browse/METAMODEL-200
>             Project: Apache MetaModel
>          Issue Type: Bug
>            Reporter: Kasper Sørensen
>
> In MetaModel we have a flag that can be set on e.g. "COUNT( * )" which indicates if the
database may approximate the number instead of doing a consistent calculation. This is good
for optimization scenarios where you don't need an actual count, just an estimate (for progress
bars and similar stuff in UIs).
> But unfortunately we don't have any syntax support for this when dealing with String
queries. Shouldn't we add that?
> I could imagine a prefix or something like that, e.g. the "tilde / ~" symbol, like this:
> {code}
> SELECT ~COUNT(*) FROM table
> {code}



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