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 ] )