2021-05-17 07:30:42 +00:00
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#include <Functions/IFunction.h>
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2018-09-08 01:24:09 +00:00
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#include <Functions/FunctionFactory.h>
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#include <DataTypes/DataTypeNullable.h>
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#include <Columns/ColumnNullable.h>
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#include <Core/ColumnNumbers.h>
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namespace DB
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{
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2020-09-07 18:00:37 +00:00
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namespace
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{
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2018-09-08 01:24:09 +00:00
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/// If value is not Nullable or NULL, wraps it to Nullable.
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class FunctionToNullable : public IFunction
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{
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public:
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static constexpr auto name = "toNullable";
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2021-04-10 23:33:54 +00:00
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static FunctionPtr create(ContextPtr)
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2018-09-08 01:24:09 +00:00
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{
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return std::make_shared<FunctionToNullable>();
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}
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std::string getName() const override
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{
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return name;
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}
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size_t getNumberOfArguments() const override { return 1; }
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bool useDefaultImplementationForNulls() const override { return false; }
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bool useDefaultImplementationForConstants() const override { return true; }
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DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
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{
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return makeNullable(arguments[0]);
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}
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2020-11-17 13:24:45 +00:00
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ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t) const override
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2018-09-08 01:24:09 +00:00
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{
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2020-10-19 15:27:41 +00:00
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return makeNullable(arguments[0].column);
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2018-09-08 01:24:09 +00:00
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}
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};
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2020-09-07 18:00:37 +00:00
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}
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2018-09-08 01:24:09 +00:00
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void registerFunctionToNullable(FunctionFactory & factory)
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{
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factory.registerFunction<FunctionToNullable>();
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}
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}
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