ClickHouse/dbms/src/AggregateFunctions/AggregateFunctionIf.cpp
2018-09-10 20:09:07 +03:00

44 lines
1.4 KiB
C++

#include <AggregateFunctions/AggregateFunctionIf.h>
#include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
class AggregateFunctionCombinatorIf final : public IAggregateFunctionCombinator
{
public:
String getName() const override { return "If"; }
DataTypes transformArguments(const DataTypes & arguments) const override
{
if (arguments.empty())
throw Exception("Incorrect number of arguments for aggregate function with " + getName() + " suffix",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
if (!isUInt8(arguments.back()))
throw Exception("Illegal type " + arguments.back()->getName() + " of last argument for aggregate function with " + getName() + " suffix",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return DataTypes(arguments.begin(), std::prev(arguments.end()));
}
AggregateFunctionPtr transformAggregateFunction(
const AggregateFunctionPtr & nested_function, const DataTypes & arguments, const Array &) const override
{
return std::make_shared<AggregateFunctionIf>(nested_function, arguments);
}
};
void registerAggregateFunctionCombinatorIf(AggregateFunctionCombinatorFactory & factory)
{
factory.registerCombinator(std::make_shared<AggregateFunctionCombinatorIf>());
}
}