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90 lines
2.4 KiB
C++
90 lines
2.4 KiB
C++
#include <Functions/IFunction.h>
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#include <Functions/FunctionFactory.h>
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#include <Functions/extractTimeZoneFromFunctionArguments.h>
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#include <DataTypes/DataTypeDateTime.h>
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#include <Columns/ColumnsDateTime.h>
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#include <Columns/ColumnVector.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 NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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extern const int ILLEGAL_TYPE_OF_ARGUMENT;
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}
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namespace
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{
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/** Returns current time at calculation of every block.
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* In contrast to 'now' function, it's not a constant expression and is not a subject of constant folding.
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*/
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class FunctionNowInBlock : public IFunction
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{
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public:
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static constexpr auto name = "nowInBlock";
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static FunctionPtr create(ContextPtr)
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{
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return std::make_shared<FunctionNowInBlock>();
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}
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String getName() const override
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{
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return name;
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}
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bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override
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{
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return false;
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}
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/// Optional timezone argument.
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bool isVariadic() const override { return true; }
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size_t getNumberOfArguments() const override { return 0; }
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bool isDeterministic() const override
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{
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return false;
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}
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bool isDeterministicInScopeOfQuery() const override
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{
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return false;
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}
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DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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{
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if (arguments.size() > 1)
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{
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throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH, "Arguments size of function {} should be 0 or 1", getName());
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}
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if (arguments.size() == 1 && !isStringOrFixedString(arguments[0].type))
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{
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throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Arguments of function {} should be String or FixedString",
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getName());
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}
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if (arguments.size() == 1)
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{
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return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 0, 0));
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}
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return std::make_shared<DataTypeDateTime>();
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}
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ColumnPtr executeImpl(const ColumnsWithTypeAndName &, const DataTypePtr &, size_t input_rows_count) const override
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{
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return ColumnDateTime::create(input_rows_count, static_cast<UInt32>(time(nullptr)));
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}
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};
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}
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REGISTER_FUNCTION(NowInBlock)
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{
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factory.registerFunction<FunctionNowInBlock>();
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}
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}
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