On 06/12/09 19:32, Philip Stubbs wrote: > Hi, > > I have been playing with mapnik to create some maps. It has been fun, > but I am a bit lacking in Postgres SQL. Can anybody help me to adjust > the following SELECT statement so that it will return a result set > that consists of only one of each distinct 'name'? > > SELECT way,highway,aeroway,name,ref,char_length(ref) AS length, > ST_Length(way) AS road_len, > CASE WHEN bridge IN ('yes','true','1') THEN 'yes'::text ELSE > bridge END AS bridge > FROM planet_osm_line > WHERE waterway IS NULL > AND leisure IS NULL > AND landuse IS NULL > AND (name IS NOT NULL OR ref IS NOT NULL) > ORDER BY road_len DESC > > Thank you all.
The default is SELECT ALL so try :- SELECT DISTINCT ON (name) way,highway,aeroway,name,ref,char_length(ref) AS length,......... -- -------------------------------------------------------------- Discover Linux - Open Source Solutions to Business and Schools http://discoverlinux.co.uk -------------------------------------------------------------- -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --------------------------------------------------------------