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32 lines
975 B
C++
32 lines
975 B
C++
#pragma once
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#include <TableFunctions/ITableFunction.h>
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#include <common/types.h>
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namespace DB
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{
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/* zeros(limit), zeros_mt(limit)
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* - the same as SELECT zero FROM system.zeros LIMIT limit.
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* Used for testing purposes, as a simple example of table function.
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*/
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template <bool multithreaded>
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class TableFunctionZeros : public ITableFunction
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{
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public:
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static constexpr auto name = multithreaded ? "zeros_mt" : "zeros";
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std::string getName() const override { return name; }
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bool hasStaticStructure() const override { return true; }
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private:
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StoragePtr executeImpl(const ASTPtr & ast_function, const Context & context, const std::string & table_name, ColumnsDescription cached_columns) const override;
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const char * getStorageTypeName() const override { return "SystemZeros"; }
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UInt64 evaluateArgument(const Context & context, ASTPtr & argument) const;
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ColumnsDescription getActualTableStructure(const Context & context) const override;
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};
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}
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