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106 lines
3.5 KiB
C++
106 lines
3.5 KiB
C++
#pragma once
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#include <Core/Block.h>
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#include <Core/NamesAndTypes.h>
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#include <Interpreters/Aliases.h>
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#include <Interpreters/SelectQueryOptions.h>
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#include <Interpreters/DatabaseAndTableWithAlias.h>
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#include <Storages/IStorage_fwd.h>
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namespace DB
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{
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class ASTFunction;
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class AnalyzedJoin;
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class Context;
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struct Settings;
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struct SelectQueryOptions;
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using Scalars = std::map<String, Block>;
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struct SyntaxAnalyzerResult
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{
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ConstStoragePtr storage;
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std::shared_ptr<AnalyzedJoin> analyzed_join;
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NamesAndTypesList source_columns;
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NameSet source_columns_set; /// Set of names of source_columns.
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/// Set of columns that are enough to read from the table to evaluate the expression. It does not include joined columns.
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NamesAndTypesList required_source_columns;
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Aliases aliases;
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std::vector<const ASTFunction *> aggregates;
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/// Which column is needed to be ARRAY-JOIN'ed to get the specified.
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/// For example, for `SELECT s.v ... ARRAY JOIN a AS s` will get "s.v" -> "a.v".
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NameToNameMap array_join_result_to_source;
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/// For the ARRAY JOIN section, mapping from the alias to the full column name.
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/// For example, for `ARRAY JOIN [1,2] AS b` "b" -> "array(1,2)" will enter here.
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/// Note: not used further.
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NameToNameMap array_join_alias_to_name;
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/// The backward mapping for array_join_alias_to_name.
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/// Note: not used further.
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NameToNameMap array_join_name_to_alias;
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/// Predicate optimizer overrides the sub queries
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bool rewrite_subqueries = false;
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/// Results of scalar sub queries
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Scalars scalars;
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bool maybe_optimize_trivial_count = false;
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SyntaxAnalyzerResult(const NamesAndTypesList & source_columns_, ConstStoragePtr storage_ = {}, bool add_virtuals = true)
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: storage(storage_)
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, source_columns(source_columns_)
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{
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collectSourceColumns(add_virtuals);
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}
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void collectSourceColumns(bool add_virtuals);
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void collectUsedColumns(const ASTPtr & query);
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Names requiredSourceColumns() const { return required_source_columns.getNames(); }
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const Scalars & getScalars() const { return scalars; }
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};
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using SyntaxAnalyzerResultPtr = std::shared_ptr<const SyntaxAnalyzerResult>;
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/// AST syntax analysis.
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/// Optimises AST tree and collect information for further expression analysis.
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/// Result AST has the following invariants:
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/// * all aliases are substituted
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/// * qualified names are translated
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/// * scalar subqueries are executed replaced with constants
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/// * unneeded columns are removed from SELECT clause
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/// * duplicated columns are removed from ORDER BY, LIMIT BY, USING(...).
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/// Motivation:
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/// * group most of the AST-changing operations in single place
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/// * avoid AST rewriting in ExpressionAnalyzer
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/// * decompose ExpressionAnalyzer
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class SyntaxAnalyzer
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{
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public:
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SyntaxAnalyzer(const Context & context_)
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: context(context_)
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{}
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/// Analyze and rewrite not select query
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SyntaxAnalyzerResultPtr analyze(ASTPtr & query, const NamesAndTypesList & source_columns_, ConstStoragePtr storage = {}) const;
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/// Analyze and rewrite select query
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SyntaxAnalyzerResultPtr analyzeSelect(
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ASTPtr & query,
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SyntaxAnalyzerResult && result,
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const SelectQueryOptions & select_options = {},
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const std::vector<TableWithColumnNamesAndTypes> & tables_with_columns = {},
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const Names & required_result_columns = {}) const;
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private:
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const Context & context;
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static void normalize(ASTPtr & query, Aliases & aliases, const Settings & settings);
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};
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}
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