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71 lines
2.5 KiB
C++
71 lines
2.5 KiB
C++
#include <Core/Block.h>
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#include <Columns/ColumnConst.h>
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#include <Columns/ColumnsNumber.h>
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#include <Parsers/ASTIdentifier.h>
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#include <Parsers/ASTLiteral.h>
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#include <Parsers/ExpressionElementParsers.h>
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#include <DataTypes/DataTypesNumber.h>
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#include <Interpreters/Context.h>
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#include <Interpreters/ExpressionAnalyzer.h>
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#include <Interpreters/ExpressionActions.h>
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#include <Interpreters/evaluateConstantExpression.h>
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#include <Common/typeid_cast.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 LOGICAL_ERROR;
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extern const int BAD_ARGUMENTS;
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}
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std::pair<Field, std::shared_ptr<const IDataType>> evaluateConstantExpression(const ASTPtr & node, const Context & context)
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{
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ExpressionActionsPtr expr_for_constant_folding = ExpressionAnalyzer(
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node, context, nullptr, NamesAndTypesList{{ "_dummy", std::make_shared<DataTypeUInt8>() }}, Names()).getConstActions();
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/// There must be at least one column in the block so that it knows the number of rows.
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Block block_with_constants{{ ColumnConst::create(ColumnUInt8::create(1, 0), 1), std::make_shared<DataTypeUInt8>(), "_dummy" }};
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expr_for_constant_folding->execute(block_with_constants);
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if (!block_with_constants || block_with_constants.rows() == 0)
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throw Exception("Logical error: empty block after evaluation of constant expression for IN or VALUES", ErrorCodes::LOGICAL_ERROR);
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String name = node->getColumnName();
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if (!block_with_constants.has(name))
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throw Exception("Element of set in IN or VALUES is not a constant expression: " + name, ErrorCodes::BAD_ARGUMENTS);
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const ColumnWithTypeAndName & result = block_with_constants.getByName(name);
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const IColumn & result_column = *result.column;
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if (!result_column.isColumnConst())
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throw Exception("Element of set in IN or VALUES is not a constant expression: " + name, ErrorCodes::BAD_ARGUMENTS);
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return std::make_pair(result_column[0], result.type);
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}
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ASTPtr evaluateConstantExpressionAsLiteral(const ASTPtr & node, const Context & context)
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{
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if (typeid_cast<const ASTLiteral *>(node.get()))
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return node;
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return std::make_shared<ASTLiteral>(evaluateConstantExpression(node, context).first);
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}
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ASTPtr evaluateConstantExpressionOrIdentifierAsLiteral(const ASTPtr & node, const Context & context)
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{
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if (auto id = typeid_cast<const ASTIdentifier *>(node.get()))
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return std::make_shared<ASTLiteral>(Field(id->name));
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return evaluateConstantExpressionAsLiteral(node, context);
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}
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}
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