risingwave_expr_impl::aggregate::general

Function count

Source 
fn count<T>(state: i64, _: T, retract: bool) -> i64
Expand description

Note the following corner cases:

statement ok
create table t(v1 int);

statement ok
insert into t values (null);

query I
select count(*) from t;
----
1

query I
select count(v1) from t;
----
0

query I
select sum(v1) from t;
----
NULL

statement ok
drop table t;