SQL to find the Size of Databases on Netezza Server

SELECT ORX.database::nvarchar(64) AS "DatabaseName",
case when sum(SOD.allocated_bytes) is null then 0 else SUM(SOD.allocated_bytes)/1073741824 end AS "AllocatedSpace_GB"
FROM _V_SYS_OBJECT_DSLICE_INFO SOD INNER JOIN _V_OBJ_RELATION_XDB ORX ON ORX.objid = SOD.tblid
WHERE ORX.database = 'MCH_SG_UAT'
GROUP BY "DatabaseName"
ORDER BY "DatabaseName"