Hi all... I'm just getting into database programming. Find it much easier than accessing large random data files. However I have a question about SQL query that I can't get to do what I want it to do.
Let me simplify it by assuming a database with three fields - City Name, Longitude, Latitude.
I'm trying to create a query that will populate an MSFlexGrid control with only those cities that start with a certain letter AND are a certain distance from a given location.
I realize that I could introduce an extra field in the database that will contain the actual distances to these cities and be done with it but the problem here is that the central location is not fixed (ie. a moving car). So in essence I have to extract the lat/lon from the database, calculate the distance, then apply the city name filter and then populate the MSFlexGrid...

I was playing around with "Select * FROM xxx WHERE..." type query and it almost does what I want it to do, but can I apply an externally calculated distance filter to it?

Any help would be greatly appreciated.

thanks


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Alex

Hi,
Presumable you have the Longitude and Latitude of the Location from which you want to calculate the distance. So to return cities within a fixed distance of that point you could search for a fixed range of Longitude and Latitude :-
WHERE ((Longitude Between x And y) AND (Latitude Between a And b))
Just one point on the naming of fields in a database - it's best not to include spaces as you will need to remember to enclose the field name in square brackets for a query, [City Name] so change it to "CityName" or  "City_Name"


[Edited by GeoffS on 27-11-2008 at 08:12 AM GMT]

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multi-tasking - the ability to hang more than one app. at the same time.