This example drops a column from a column partition of orders and modifies that partition to become a two-column partition with system-determined COLUMN format and autocompression.
ALTER TABLE orders DROP o_comment_ext2;
This results in the following table definition.
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_comment VARCHAR(79), o_salesperson VARCHAR(5), o_ordersubstatus CHARACTER(1) CASESPECIFIC, o_comment_ext1 VARCHAR(79), o_ship_addr VARCHAR(500), o_bill_addr VARCHAR(200), o_alt_ship_addr VARCHAR(500), o_alt_bill_addr VARCHAR(200), o_item_count INTEGER ) PARTITION BY (COLUMN ALL BUT ((o_orderstatus, o_ordersubstatus), (o_comment, o_comment_ext1), ROW(o_ship_addr, o_bill_addr) NO AUTO COMPRESS, COLUMN(o_alt_ship_addr, o_alt_bill_addr)) ADD 1, 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);