ClickHouse/dbms/src/AggregateFunctions/AggregateFunctionAvg.cpp

#include <DB/AggregateFunctions/AggregateFunctionFactory.h>
#include <DB/AggregateFunctions/AggregateFunctionAvg.h>
#include <DB/AggregateFunctions/Helpers.h>

namespace DB
{

namespace
{

AggregateFunctionPtr createAggregateFunctionAvg(const std::string & name, const DataTypes & argument_types)
{
    if (argument_types.size() != 1)
        throw Exception("Incorrect number of arguments for aggregate function " + name, ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);

    AggregateFunctionPtr res(createWithNumericType<AggregateFunctionAvg>(*argument_types[0]));

    if (!res)
        throw Exception("Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name, ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

    return res;
}

}

void registerAggregateFunctionAvg(AggregateFunctionFactory & factory)
{
    factory.registerFunction("avg", createAggregateFunctionAvg, AggregateFunctionFactory::CaseInsensitive);
}

}