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52 lines
1.7 KiB
C++
52 lines
1.7 KiB
C++
#include <TableFunctions/ITableFunction.h>
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#include <TableFunctions/TableFunctionNumbers.h>
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#include <TableFunctions/TableFunctionFactory.h>
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#include <Parsers/ASTFunction.h>
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#include <Parsers/ASTLiteral.h>
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#include <Common/typeid_cast.h>
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#include <Storages/System/StorageSystemNumbers.h>
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#include <Interpreters/evaluateConstantExpression.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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}
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StoragePtr TableFunctionNumbers::executeImpl(const ASTPtr & ast_function, const Context & context) const
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{
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if (const ASTFunction * function = typeid_cast<ASTFunction *>(ast_function.get()))
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{
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auto arguments = function->arguments->children;
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if (arguments.size() != 1 && arguments.size() != 2)
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throw Exception("Table function 'numbers' requires 'length' or 'offset, length'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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UInt64 offset = arguments.size() == 2 ? evaluateArgument(context, arguments[0]) : 0;
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UInt64 length = arguments.size() == 2 ? evaluateArgument(context, arguments[1]) : evaluateArgument(context, arguments[0]);
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auto res = StorageSystemNumbers::create(getName(), false, length, offset);
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res->startup();
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return res;
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}
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throw new Exception("Table function 'numbers' requires 'limit' or 'offset, limit'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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}
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void registerTableFunctionNumbers(TableFunctionFactory & factory)
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{
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factory.registerFunction<TableFunctionNumbers>();
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}
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UInt64 TableFunctionNumbers::evaluateArgument(const Context & context, ASTPtr & argument) const
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{
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return static_cast<const ASTLiteral &>(*evaluateConstantExpressionOrIdentifierAsLiteral(argument, context)).value.safeGet<UInt64>();
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}
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}
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