ClickHouse/src/Functions/date_trunc.cpp

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#include <Columns/ColumnConst.h>
#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnString.h>
#include <DataTypes/DataTypeDate.h>
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeInterval.h>
#include <Functions/DateTimeTransforms.h>
#include <Functions/FunctionFactory.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
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extern const int BAD_ARGUMENTS;
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}
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namespace
{
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class FunctionDateTrunc : public IFunction
{
public:
static constexpr auto name = "date_trunc";
explicit FunctionDateTrunc(ContextPtr context_) : context(context_) {}
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static FunctionPtr create(ContextPtr context) { return std::make_shared<FunctionDateTrunc>(context); }
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String getName() const override { return name; }
bool isVariadic() const override { return true; }
size_t getNumberOfArguments() const override { return 0; }
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
{
/// The first argument is a constant string with the name of datepart.
auto result_type_is_date = false;
String datepart_param;
auto check_first_argument = [&] {
const ColumnConst * datepart_column = checkAndGetColumnConst<ColumnString>(arguments[0].column.get());
if (!datepart_column)
throw Exception("First argument for function " + getName() + " must be constant string: name of datepart",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
datepart_param = datepart_column->getValue<String>();
if (datepart_param.empty())
throw Exception("First argument (name of datepart) for function " + getName() + " cannot be empty",
ErrorCodes::BAD_ARGUMENTS);
if (!IntervalKind::tryParseString(datepart_param, datepart_kind))
throw Exception(datepart_param + " doesn't look like datepart name in " + getName(),
ErrorCodes::BAD_ARGUMENTS);
result_type_is_date = (datepart_kind == IntervalKind::Year)
|| (datepart_kind == IntervalKind::Quarter) || (datepart_kind == IntervalKind::Month)
|| (datepart_kind == IntervalKind::Week);
};
bool second_argument_is_date = false;
auto check_second_argument = [&] {
if (!isDateOrDateTime(arguments[1].type))
throw Exception(
"Illegal type " + arguments[1].type->getName() + " of 2nd argument of function " + getName()
+ ". Should be a date or a date with time",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
second_argument_is_date = isDate(arguments[1].type);
if (second_argument_is_date && ((datepart_kind == IntervalKind::Hour)
|| (datepart_kind == IntervalKind::Minute) || (datepart_kind == IntervalKind::Second)))
throw Exception("Illegal type Date of argument for function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
};
auto check_timezone_argument = [&] {
if (!WhichDataType(arguments[2].type).isString())
throw Exception(
"Illegal type " + arguments[2].type->getName() + " of argument of function " + getName()
+ ". This argument is optional and must be a constant string with timezone name",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (second_argument_is_date && result_type_is_date)
throw Exception(
"The timezone argument of function " + getName() + " with datepart '" + datepart_param
+ "' is allowed only when the 2nd argument has the type DateTime",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
};
if (arguments.size() == 2)
{
check_first_argument();
check_second_argument();
}
else if (arguments.size() == 3)
{
check_first_argument();
check_second_argument();
check_timezone_argument();
}
else
{
throw Exception(
"Number of arguments for function " + getName() + " doesn't match: passed " + toString(arguments.size())
+ ", should be 2 or 3",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
}
if (result_type_is_date)
return std::make_shared<DataTypeDate>();
else
return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 2, 1));
}
bool useDefaultImplementationForConstants() const override { return true; }
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {0, 2}; }
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
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{
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ColumnsWithTypeAndName temp_columns(arguments.size());
temp_columns[0] = arguments[1];
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const UInt16 interval_value = 1;
const ColumnPtr interval_column = ColumnConst::create(ColumnInt64::create(1, interval_value), input_rows_count);
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temp_columns[1] = {interval_column, std::make_shared<DataTypeInterval>(datepart_kind), ""};
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auto to_start_of_interval = FunctionFactory::instance().get("toStartOfInterval", context);
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if (arguments.size() == 2)
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return to_start_of_interval->build(temp_columns)->execute(temp_columns, result_type, input_rows_count);
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temp_columns[2] = arguments[2];
return to_start_of_interval->build(temp_columns)->execute(temp_columns, result_type, input_rows_count);
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}
bool hasInformationAboutMonotonicity() const override
{
return true;
}
Monotonicity getMonotonicityForRange(const IDataType &, const Field &, const Field &) const override
{
return { true, true, true };
}
private:
ContextPtr context;
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mutable IntervalKind::Kind datepart_kind = IntervalKind::Kind::Second;
};
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}
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void registerFunctionDateTrunc(FunctionFactory & factory)
{
factory.registerFunction<FunctionDateTrunc>(FunctionFactory::CaseInsensitive);
/// Compatibility alias.
factory.registerAlias("dateTrunc", FunctionDateTrunc::name);
}
}