[postgis-devel] [PostGIS] #544: alias construct fails in SELECT

PostGIS trac at osgeo.org
Thu Jun 17 04:58:15 PDT 2010


#544: alias construct fails in SELECT
------------------------+---------------------------------------------------
  Reporter:  darkblueb  |       Owner:  pramsey      
      Type:  defect     |      Status:  closed       
  Priority:  medium     |   Milestone:  PostGIS 1.5.2
 Component:  postgis    |     Version:  1.5.X        
Resolution:  invalid    |    Keywords:               
------------------------+---------------------------------------------------
Changes (by mcayland):

  * status:  new => closed
  * resolution:  => invalid


Comment:

 This suggests to me that "area" is already defined somewhere else in theq
 query - perhaps it is already a column within your constrained_sum2 or
 ct_sac_0 tables?

 I know that per the SQL spec, you are not allowed to reference an existing
 column alias within a select, e.g.

 SELECT st_area(col) AS foo, foo / 10 AS bar

 is illegal. You need to repeat it again, e.g.

 SELECT st_area(col) AS foo, st_area(col) / 10 AS bar


 HTH,

 Mark.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/544#comment:1>
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