| avg(expression) | smallint, integer,
       bigint, real, double
       precision, numeric, or interval. | numeric for any integer type argument,
       double precision for a floating-point argument,
       otherwise the same as the argument data type | the average (arithmetic mean) of all input values |  | 
| count(*) |  | bigint | number of input values |  | 
| count(expression) | any | bigint | number of input values for which the value of expression is not null |  | 
| max(expression) | any numeric, string, or date/time type | same as argument type | maximum value of expression across all input
       values |  | 
| min(expression) | any numeric, string, or date/time type | same as argument type | minimum value of expression across all input
       values |  | 
| stddev(expression) | smallint, integer,
       bigint, real, double
       precision, or numeric. | double precision for floating-point arguments,
       otherwise numeric. | sample standard deviation of the input values |  | 
| sum(expression) | smallint, integer,
       bigint, real, double
       precision, numeric, or
       interval | bigint for smallint or
       integer arguments, numeric for
       bigint arguments, double precision
       for floating-point arguments, otherwise the same as the
       argument data type | sum of expression across all input values |  | 
| variance(expression) | smallint, integer,
       bigint, real, double
       precision, or numeric. | double precision for floating-point arguments,
       otherwise numeric. | sample variance of the input values (square of the sample standard deviation) |  |