"Thalis A. Kalfigopoulos" <thalis@cs.pitt.edu> writes:
> In the manual fro creating aggregate functions (http://www.postgresql.org/idocs/index.php?sql-createaggregate.html)
itreads:
> --->Alternatively, for an aggregate that does not examine its input
> values, the function takes just one argument of type
> state_type<---.
Yup. It also says
input_data_type
The input data type on which this aggregate function operates. This
can be specified as ANY for an aggregate that
does not examine its input values (an example is count(*)).
Perhaps "can" is the wrong word there, you *must* say ANY if your
aggregate is input-value-independent.
regards, tom lane