CREATE AGGREGATE name ( BASETYPE = input_data_type [ , SFUNC1 = sfunc1, STYPE1 = state1_type ] [ , SFUNC2 = sfunc2, STYPE2 = state2_type ] [ , FINALFUNC = ffunc ] [ , INITCOND1 = initial_condition1 ] [ , INITCOND2 = initial_condition2 ] )