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44 lines
1.5 KiB
C++
44 lines
1.5 KiB
C++
#pragma once
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#include <Interpreters/ColumnNamesContext.h>
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#include <Interpreters/InDepthNodeVisitor.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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}
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class ASTIdentifier;
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class ASTFunction;
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class ASTSelectQuery;
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struct ASTTablesInSelectQueryElement;
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struct ASTArrayJoin;
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struct ASTTableExpression;
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class RequiredSourceColumnsMatcher
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{
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public:
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using Visitor = ConstInDepthNodeVisitor<RequiredSourceColumnsMatcher, false>;
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using Data = ColumnNamesContext;
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static bool needChildVisit(const ASTPtr & node, const ASTPtr & child);
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static void visit(const ASTPtr & ast, Data & data);
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private:
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static void visit(const ASTIdentifier & node, const ASTPtr &, Data & data);
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static void visit(const ASTFunction & node, const ASTPtr &, Data & data);
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static void visit(const ASTTablesInSelectQueryElement & node, const ASTPtr &, Data & data);
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static void visit(const ASTTableExpression & node, const ASTPtr &, Data & data);
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static void visit(const ASTArrayJoin & node, const ASTPtr &, Data & data);
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static void visit(const ASTSelectQuery & select, const ASTPtr &, Data & data);
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};
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/// Extracts all the information about columns and tables from ASTSelectQuery block into ColumnNamesContext object.
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/// It doesn't use anything but AST. It visits nodes from bottom to top except ASTFunction content to get aliases in right manner.
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/// @note There's some ambiguousness with nested columns names that can't be solved without schema.
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using RequiredSourceColumnsVisitor = RequiredSourceColumnsMatcher::Visitor;
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}
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