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148 lines
4.7 KiB
C++
148 lines
4.7 KiB
C++
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#pragma once
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#include <Parsers/ASTFunction.h>
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#include <Parsers/queryToString.h>
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#include <Interpreters/InDepthNodeVisitor.h>
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#include <Interpreters/SyntaxAnalyzer.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 INVALID_JOIN_ON_EXPRESSION;
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}
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class CollectJoinOnKeysMatcher
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{
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public:
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using Visitor = ConstInDepthNodeVisitor<CollectJoinOnKeysMatcher, true>;
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struct Data
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{
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AnalyzedJoin & analyzed_join;
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bool has_some = false;
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};
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static void visit(const ASTPtr & ast, Data & data)
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{
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if (auto * func = ast->as<ASTFunction>())
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visit(*func, ast, data);
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}
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static bool needChildVisit(const ASTPtr & node, const ASTPtr &)
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{
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if (auto * func = node->as<ASTFunction>())
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if (func->name == "equals")
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return false;
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return true;
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}
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private:
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static void visit(const ASTFunction & func, const ASTPtr & ast, Data & data)
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{
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if (func.name == "and")
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return; /// go into children
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if (func.name == "equals")
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{
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ASTPtr left = func.arguments->children.at(0)->clone();
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ASTPtr right = func.arguments->children.at(1)->clone();
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addColumnsFromEqualsExpr(ast, left, right, data);
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return;
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}
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throwSyntaxException("Expected equals expression, got " + queryToString(ast) + ".");
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}
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static void getIdentifiers(const ASTPtr & ast, std::vector<const ASTIdentifier *> & out)
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{
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if (const auto * ident = ast->as<ASTIdentifier>())
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{
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if (IdentifierSemantic::getColumnName(*ident))
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out.push_back(ident);
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return;
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}
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for (const auto & child : ast->children)
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getIdentifiers(child, out);
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}
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static void addColumnsFromEqualsExpr(const ASTPtr & expr, ASTPtr left_ast, ASTPtr right_ast, Data & data)
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{
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std::vector<const ASTIdentifier *> left_identifiers;
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std::vector<const ASTIdentifier *> right_identifiers;
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getIdentifiers(left_ast, left_identifiers);
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getIdentifiers(right_ast, right_identifiers);
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size_t left_idents_table = checkSameTable(left_identifiers);
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size_t right_idents_table = checkSameTable(right_identifiers);
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if (left_idents_table && left_idents_table == right_idents_table)
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{
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auto left_name = queryToString(*left_identifiers[0]);
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auto right_name = queryToString(*right_identifiers[0]);
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throwSyntaxException("In expression " + queryToString(expr) + " columns " + left_name + " and " + right_name
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+ " are from the same table but from different arguments of equal function.");
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}
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if (left_idents_table == 1 || right_idents_table == 2)
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data.analyzed_join.addOnKeys(left_ast, right_ast);
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else if (left_idents_table == 2 || right_idents_table == 1)
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data.analyzed_join.addOnKeys(right_ast, left_ast);
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else
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{
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/// Default variant when all identifiers may be from any table.
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data.analyzed_join.addOnKeys(left_ast, right_ast); /// FIXME
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}
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data.has_some = true;
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}
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static size_t checkSameTable(std::vector<const ASTIdentifier *> & identifiers)
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{
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size_t table_number = 0;
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const ASTIdentifier * detected = nullptr;
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for (const auto & identifier : identifiers)
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{
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/// It's set in TranslateQualifiedNamesVisitor
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size_t membership = IdentifierSemantic::getMembership(*identifier);
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if (membership && table_number == 0)
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{
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table_number = membership;
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detected = identifier;
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}
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if (membership && membership != table_number)
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{
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throw Exception("Invalid columns in JOIN ON section. Columns "
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+ detected->getAliasOrColumnName() + " and " + identifier->getAliasOrColumnName()
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+ " are from different tables.", ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
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}
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}
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identifiers.clear();
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if (detected)
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identifiers.push_back(detected);
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return table_number;
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}
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[[noreturn]] static void throwSyntaxException(const String & msg)
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{
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throw Exception("Invalid expression for JOIN ON. " + msg +
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" Supported syntax: JOIN ON Expr([table.]column, ...) = Expr([table.]column, ...) "
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"[AND Expr([table.]column, ...) = Expr([table.]column, ...) ...]",
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ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
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}
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};
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/// Parse JOIN ON expression and collect ASTs for joined columns.
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using CollectJoinOnKeysVisitor = CollectJoinOnKeysMatcher::Visitor;
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}
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