This example drops two columns from a column partition, and because that leaves the partitions with no columns, also drops the column partition.
ALTER TABLE orders DROP o_alt_ship_addr, DROP o_alt_bill_addr;
This results in a table definition as follows. note that ADD option value for level 1 increases to 3.
CREATE TABLE orders ( o_orderkey INTEGER NOT NULL, o_custkey INTEGER, o_orderstatus CHARACTER(1) CASESPECIFIC, o_totalprice DECIMAL(13,2) NOT NULL, o_ordertsz TIMESTAMP(6) WITH TIME ZONE NOT NULL, o_salesperson VARCHAR(5), o_ordersubstatus CHARACTER(1) CASESPECIFIC, o_ship_addr VARCHAR(500), o_bill_addr VARCHAR(200), o_item_count INTEGER ) PARTITION BY (COLUMN ALL BUT ( (o_orderstatus, o_ordersubstatus), ROW(o_ship_addr, o_bill_addr) NO AUTO COMPRESS) ADD 3, RANGE_N(o_ordertsz BETWEEN TIMESTAMP '2003-01-01 00:00:00.000000+00:00' AND TIMESTAMP '2009-12-31 23:59:59.999999+00:00' EACH INTERVAL '1' MONTH) ), UNIQUE INDEX(o_orderkey);