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76 lines
2.3 KiB
C++
76 lines
2.3 KiB
C++
#include <Functions/IFunction.h>
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#include <Functions/FunctionFactory.h>
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#include <DataTypes/DataTypeString.h>
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#include <DataTypes/DataTypeNullable.h>
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#include <DataTypes/DataTypeDateTime.h>
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#include <common/DateLUTImpl.h>
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#include <Core/Field.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int BAD_ARGUMENTS;
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}
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namespace
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{
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/** timezoneOf(x) - get the name of the timezone of DateTime data type.
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* Example: Europe/Moscow.
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*/
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class FunctionTimezoneOf : public IFunction
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{
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public:
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static constexpr auto name = "timezoneOf";
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String getName() const override { return name; }
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static FunctionPtr create(ContextPtr) { return std::make_unique<FunctionTimezoneOf>(); }
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size_t getNumberOfArguments() const override { return 1; }
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DataTypePtr getReturnTypeImpl(const DataTypes & types) const override
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{
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DataTypePtr type_no_nullable = removeNullable(types[0]);
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if (isDateTime(type_no_nullable) || isDateTime64(type_no_nullable))
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return std::make_shared<DataTypeString>();
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else
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throw Exception(ErrorCodes::BAD_ARGUMENTS, "Bad argument for function {}, should be DateTime or DateTime64", name);
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}
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bool useDefaultImplementationForNulls() const override { return false; }
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bool useDefaultImplementationForLowCardinalityColumns() const override { return false; }
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ColumnNumbers getArgumentsThatDontImplyNullableReturnType(size_t /*number_of_arguments*/) const override { return {0}; }
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ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
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{
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DataTypePtr type_no_nullable = removeNullable(arguments[0].type);
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return DataTypeString().createColumnConst(input_rows_count,
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dynamic_cast<const TimezoneMixin &>(*type_no_nullable).getTimeZone().getTimeZone());
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}
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ColumnPtr getConstantResultForArguments(const ColumnsWithTypeAndName & arguments) const override
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{
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DataTypePtr type_no_nullable = removeNullable(arguments[0].type);
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return DataTypeString().createColumnConst(1,
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dynamic_cast<const TimezoneMixin &>(*type_no_nullable).getTimeZone().getTimeZone());
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}
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};
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}
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void registerFunctionTimezoneOf(FunctionFactory & factory)
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{
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factory.registerFunction<FunctionTimezoneOf>();
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factory.registerAlias("timeZoneOf", "timezoneOf");
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}
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}
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