On Mon, Dec 22, 2003 at 04:54:01PM +0800, Daniel Lau wrote: > I am wondering if we are able to extract the x-coordinate from a > point-type attribute with SQL. I have been looking for this sort of > functions from documents and websites but it seems the function does not > exist. Or, any altnernate to do so?
>From the bottom of the Geometric Functions and Operators chapter of the documentation: "It is possible to access the two component numbers of a point as though it were an array with indices 0 and 1. For example, if t.p is a point column then SELECT p[0] FROM t retrieves the X coordinate and UPDATE t SET p[1] = ... changes the Y coordinate. In the same way, a value of type box or lseg may be treated as an array of two point values." http://www.postgresql.org/docs/current/static/functions-geometry.html -- Michael Fuhr http://www.fuhr.org/~mfuhr/ ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
