[mapserver-users] PostGIS Data Query vs Expression

[Gregor Karzelek]

Hi,

Personally I would advice to use FILTER for that. FILTER is passed directly to the PostGIS DB as Part of the SQL WHERE and this way you can distinct more easily between "FROM" (DATA) and "WHERE" (FILTER).

For example in combination with OSM one can re-use the DATA for different road categories and distinct which objects to load via FILTER (e.g. FILTER "type in ('primarily', 'primarily_link')" ).


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Gregor Karzelek
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Am 07.02.2014 um 16:51 schrieb "Travis Kirstine" <traviskirstine at gmail.com<mailto:traviskirstine at gmail.com>>:

What is the best practice for using selecting data with a where clause in MapServer using PostGIS connection

i.e.

DATA "the_geom from (SELECT gid, the_geom FROM audience_table WHERE audience = 'Farmers') as foo using unique gid using SRID=4326"

OR

DATA "the_geom from audience_table using SRID=4326"

with a class expression

CLASSITEM audience
....
EXPRESSION 'Farmer'

Thanks

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