contrib/clickhouse/src/AggregateFunctions/AggregateFunctionCount.cpp


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#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <AggregateFunctions/AggregateFunctionCount.h>
#include <AggregateFunctions/FactoryHelpers.h>


namespace DB
{
struct Settings;

AggregateFunctionPtr AggregateFunctionCount::getOwnNullAdapter(
    const AggregateFunctionPtr &, const DataTypes & types, const Array & params, const AggregateFunctionProperties & /*properties*/) const
{
    return std::make_shared<AggregateFunctionCountNotNullUnary>(types[0], params);
}

namespace
{

AggregateFunctionPtr createAggregateFunctionCount(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
{
    assertNoParameters(name, parameters);
    assertArityAtMost<1>(name, argument_types);

    return std::make_shared<AggregateFunctionCount>(argument_types);
}

}

void registerAggregateFunctionCount(AggregateFunctionFactory & factory)
{
    AggregateFunctionProperties properties = { .returns_default_when_only_null = true, .is_order_dependent = false };
    factory.registerFunction("count", {createAggregateFunctionCount, properties}, AggregateFunctionFactory::CaseInsensitive);
}

}