Re: [Sqlalchemy-tickets] [sqlalchemy] #1068: render 'SELECT foo() AS x .. ORDER BY x' by default

[sqlalchemy <mi...@zz...>]

#1068: render 'SELECT foo() AS x .. ORDER BY x' by default
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    Reporter:  jek                |       Owner:  anyone           
        Type:  enhancement        |      Status:  new              
    Priority:  medium             |   Milestone:  0.5.xx           
   Component:  sql                |    Severity:  major - 1-3 hours
  Resolution:                     |    Keywords:                   
Status_field:  needs a volunteer  |  
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Changes (by zzzeek):

  * severity:  no triage selected yet => major - 1-3 hours

Comment:

 just a few thoughts here:

  * the work to be done here is to do a check if a label used within ORDER
 BY is present in the select() construct being rendered.
  * Postgres has a more strict policy regarding labels in ORDER BY - you
 can't embed the label into an expression of its own, it has to stand by
 itself with an optional ASC or DESC and that's it.
  * sqlite and mysql allow the label to be further calculated in an
 expression
  * I didn't check, but I have a feeling that labels cannot be used in the
 WHERE clause with postgres.  I'm also fairly certain (again didn't check)
 that Oracle never allows labels in WHERE or ORDER BY.
  * I'm gathering that MySQL allows the label to be used anywhere.
  * The compiler will probably limit its search for the label to the
 columns clause of the select() construct that is currently at the top of
 the "select stack".
  * A lot of effort is needed with testing here (the tests I did are
 obviously not enough).
  * The whole feature is strictly a more natural and convenient way of
 issuing an optimization that is available in any case, by forcing usage of
 a label name with `column('name')`.

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/1068#comment:13>
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