ARRAY_AGG and COUNT

Hi all!

I am working on a query to identify which group ids exists within a spatial
cell. In this case i have the GREG table which has polygon data and the
priogrid_land which have the cell polygon.
I want to identify which and how many GREG group ids exists within each of
the priogrid_land cells.

I have tried the below query, but i cannot find a way to select only
DISTINCT into the ARRAY_AGG function. I also do not want 0 to be included in
the array or 0 to be counted.

Any suggestions on how to accomplish the above?
Thanks!

Code:

SELECT priogrid_land.gid, priogrid_land.cell,
array_to_string(array_agg(g1id), ';') AS g1list,
array_to_string(array_agg(g2id), ';') AS g2list,
array_to_string(array_agg(g3id), ';') AS g3list,
count(distinct g1id) AS g1count, count(distinct g2id) AS g2count,
count(distinct g3id) AS g3count
INTO greg_list
FROM "GREG", priogrid_land WHERE ST_Intersects("GREG".the_geom,
priogrid_land.cell)
GROUP BY priogrid_land.gid, priogrid_land.cell;

This will give this result:
g1list; g2list; g3list; g1count; g2count; g3count
"482";"0";"0";1;1;1
"23;482;482";"0;0;0";"0;0;0";2;1;1
"1227;482;23";"0;0;0";"0;0;0";3;1;1
"1227;23;482;66";"0;0;0;0";"0;0;0;0";4;1;1
"1227;23;66";"0;0;0";"0;0;0";3;1;1

As you see i.e. in g1list 482 is counted twice in row 2. 0 is also counted.
The distinct works for count, but not for array_agg.

Cheers.