Greetings,
I am rather new to PostGIS and somewhat new to SQL, so please bear with me. I have a question about a query. I have two spatial tables, OK_Cites and OKCounties. The former is a list of various cities and towns in Oklahoma and the latter is all of the counties in Oklahoma. While investigating the OK_Cities table, I discovered only 75 cities are coded as county seats. This is peculiar because there are 77 counties in Oklahoma, so there should be 77 county seats. I decided I would try to do a query to figure out which two counties do NOT have an associated city with attributed as a county seat. I know how to easily select all of the counties which DO have a city attributed as county seat. For example: select c1.name, c2.name from OK_Cities c1, OKCounties c2 where st_within(c1.the_geom,c2.the_geom)='T' AND c1.feature='County Seat' Order by c2.Name asc; This returns 75 rows, as expected. Now, I want to find those counties in which a selected city is NOT within. I have tried this a number of ways, but am obviously doing something wrong. For instance, if I set st_within to 'F', I get a record of all county seats that are not within a county (so, for county X, there are 74 county seats that are not within it). I thought a subquery might work, but I am doing something painfully wrong with the syntax. Any suggestions? Todd Fagin Coordinate Solutions, Inc. 2804 NW 18th St. Oklahoma City, OK 73107 405.740.4324 (voice) 904.471.5548 (fax) www.coordinatesolutions.com
_______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
