[postgis-users] How to store and query a 3D dataset?

[kuien_liu]

 Hi, 
Can anybody help me with this please? 
I want to store a set of 3D elements within PostGIS, and query how many elements in special 3D spatial space later,i.e. <x1 y1 z1, x2 y2 z2> . How can I achieve it? 
I found a similar mail "http://postgis.refractions.net/pipermail/postgis-users/2007-April/015197.html" which had been posted months ago, but without unambiguous solutions to use for reference. 
Please help. 
Cheers, 
Kuien Liu