Struct CountFunc 

pub struct CountFunc;

count(X) — counts non-NULL values of X.

Trait Implementations

impl AggregateFunction for CountFunc

type State = i64

The per-group accumulator type.

fn initial_state(&self) -> Self::State

Create a fresh accumulator (zero/identity state).

fn step(&self, state: &mut Self::State, args: &[SqliteValue]) -> Result<()>

Process one row, updating the accumulator.

fn finalize(&self, state: Self::State) -> Result<SqliteValue>

Consume the accumulator and produce the final result.

fn num_args(&self) -> i32

The number of arguments this function accepts (-1 = variadic).

fn name(&self) -> &str

The function name, used in error messages and EXPLAIN output.

fn min_args(&self) -> i32

Minimum accepted SQL argument count for a variadic function.

fn max_args(&self) -> Option<i32>

Maximum accepted SQL argument count for a variadic function.

fn arity(&self) -> FunctionArity

Return the complete SQL-visible arity contract in one metadata call.