Create count(*) query based on SelectQuery

From: Andreas Hartmann (andrea..pache.org)
Date: Wed Jan 20 2010 - 11:10:43 EST

  • Next message: Andrus Adamchik: "Re: Create count(*) query based on SelectQuery"

    Hi everyone,

    I'm mainly using SelectQuery queries, built using quite a complex
    programmatic infrastructure. But now I have the requirement to obtain
    the total number of rows (to set the Content-Range header in a REST
    service).

    So basically I have a SelectQuery which does

       SELECT … FROM foo WHERE <whereClause> LIMIT … OFFSET …;

    and I need

       SELECT count(*) FROM foo WHERE <whereClause>;

    Is there a straightforward way to build such a query based on the
    SelectQuery's expression? I tried Expression.toEJBQL() but faced a
    couple of problems which have already been described on this list (e.g.
    the likeIgnoreCase issue).

    Do I really have to build a string-based SQL or EJBQL query from scratch?

    Thanks a lot for any hints!

    Best regards,
    Andreas 

    -- 
Andreas Hartmann, CTO
BeCompany GmbH
http://www.becompany.ch
Tel.: +41 (0) 43 818 57 01

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