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59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
#pragma once
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#include <Core/Field.h>
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#include <Parsers/ASTWithAlias.h>
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#include <Parsers/TokenIterator.h>
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#include <Common/FieldVisitorDump.h>
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#include <optional>
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namespace DB
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{
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/// Literal (atomic) - number, string, NULL
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class ASTLiteral : public ASTWithAlias
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{
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public:
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explicit ASTLiteral(Field value_) : value(std::move(value_)) {}
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Field value;
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/// For ConstantExpressionTemplate
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std::optional<TokenIterator> begin;
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std::optional<TokenIterator> end;
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/*
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* The name of the column corresponding to this literal. Only used to
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* disambiguate the literal columns with the same display name that are
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* created at the expression analyzer stage. In the future, we might want to
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* have a full separation between display names and column identifiers. For
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* now, this field is effectively just some private EA data.
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*/
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String unique_column_name;
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/// For compatibility reasons in distributed queries,
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/// we may need to use legacy column name for tuple literal.
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bool use_legacy_column_name_of_tuple = false;
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/** Get the text that identifies this element. */
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String getID(char delim) const override { return "Literal" + (delim + applyVisitor(FieldVisitorDump(), value)); }
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ASTPtr clone() const override;
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void updateTreeHashImpl(SipHash & hash_state) const override;
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protected:
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void formatImplWithoutAlias(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;
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void appendColumnNameImpl(WriteBuffer & ostr) const override;
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private:
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/// Legacy version of 'appendColumnNameImpl'. It differs only with tuple literals.
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/// It's only needed to continue working of queries with tuple literals
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/// in distributed tables while rolling update.
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void appendColumnNameImplLegacy(WriteBuffer & ostr) const;
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};
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}
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