I have a polygon feature class with more than 100,000 polygons in DB2 table. I would like to dissolve them based on a single field to reduce the row numbers. Is there any commands / SQL in DB2 to dissolve these without using ArcGIS Desktop tool?
You could try a variation on the union aggregate function. No idea if this has been implemted in DB2
Failing that if you can link up to QGIS then it has a default dissolve command which you can use on shape files if you have to as well so if you can't link if you could get the polygon into a shape format you could then perform the dissolve before returning the information to the database.
Warning dissolves on large datasets take a long time to process - I have had dissolves take 36 hours plus and that was for only 20,000 polygons so yours may take a significant longer amount of time.