Table alias in Expression LabelItem in map files

[Dave Potts]

I am using the mapserver map file interface to access a postgres 
database, if I attempt to use a table aliases in a LABELITEM or 
EXPRESSION clause in the map file I get a syntax error reported from the 
postgres database

eg msDrawMap(): Image handling error. Failed to draw layer named 'castles'.
prepare_database(): Query error. Error executing POSTGIS DECLARE (the 
actual query) statement: 'DECLARE mycursor BINARY CURSOR FOR SELECT 
pnt.place_name::text,certain::text,castle_name::text,asbinary(force_collection(force_2d(gis_ngr)),'NDR'),castle_id::text 
from (select ct.castle_id, ct.gis_ngr ,ct.certain, ct.possible, 
ct.question,ct.castle_name, pnt.place_name, distance(pnt.gis_ngr, 
ct.gis_ngr) from castle_table ct,place_name_table pnt, county_table 
where county_table.county_id= ct.county_id and pnt.county_id = 
county_table.county_id and county_table.county_name='Surrey' ) as foo 
WHERE gis_ngr && setSRID('BOX3D(454541.666665 
119270.833332,579541.666669 181770.833334)'::BOX3D, 27700 )'

Postgresql reports the error as 'ERROR: missing FROM-clause entry for 
table "pnt"'

For the input
===========================================================
LABELITEM "pnt.place_name"
        CONNECTIONTYPE POSTGIS
        CONNECTION "dbname=castle user=dp42 host=localhost port=5432"
        #DATA "gis_ngr from (select castle_id, gis_ngr ,certain, 
possible, question,castle_name  from  castle_table,county_table where 
county_table.county_id= castle_table.county_id and 
county_table.county_name='Surrey'  ) as foo using srid=27700 using 
unique castle_id"

        DATA "gis_ngr from (select ct.castle_id, ct.gis_ngr ,ct.certain, 
ct.possible, ct.question,ct.castle_name, pnt.place_name, 
distance(pnt.gis_ngr, ct.gis_ngr)
                           from  castle_table ct,place_name_table pnt,
                            county_table where county_table.county_id= 
ct.county_id and
                            pnt.county_id = county_table.county_id and
                                county_table.county_name='Surrey'  ) as 
foo using srid=27700 using unique castle_id"

        CLASS
                NAME "Manor Sites"
                SYMBOL 'circle'
                SIZE 3
                OUTLINECOLOR 255 0 0
                EXPRESSION ( "[certain]" =  "t" and  "[castle_name]" !=  
"%sitename%"  and distance < %sitedistance% )
                LABEL
======================================================
If I remove the table alias, ie say LABELITEM "place_name" everything is 
ok, is there a way round this problem ?

Its mapserver  4.10

regards

David.
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