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Merge pull request #8385 from 4ertus2/joins

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Relax ambiguous column check for multiple JOIN ON section
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alexey-milovidov 2019-12-25 01:28:17 +03:00 committed by GitHub
commit 1150169e55
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11 changed files with 88 additions and 22 deletions
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8
dbms/src/Interpreters/AnalyzedJoin.cpp
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@ -98,14 +98,6 @@ NameSet AnalyzedJoin::getQualifiedColumnsSet() const
return out;
}
NameSet AnalyzedJoin::getOriginalColumnsSet() const
{
NameSet out;
for (const auto & names : original_names)
out.insert(names.second);
return out;
}
NamesWithAliases AnalyzedJoin::getNamesWithAliases(const NameSet & required_columns) const
{
NamesWithAliases out;

1
dbms/src/Interpreters/AnalyzedJoin.h
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@ -96,7 +96,6 @@ public:
bool hasOn() const { return table_join.on_expression != nullptr; }
NameSet getQualifiedColumnsSet() const;
NameSet getOriginalColumnsSet() const;
NamesWithAliases getNamesWithAliases(const NameSet & required_columns) const;
NamesWithAliases getRequiredColumns(const Block & sample, const Names & action_columns) const;

17
dbms/src/Interpreters/CollectJoinOnKeysVisitor.cpp
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@ -170,11 +170,22 @@ size_t CollectJoinOnKeysMatcher::getTableForIdentifiers(std::vector<const ASTIde
if (!membership)
{
const String & name = identifier->name;
bool in_left_table = data.source_columns.count(name);
bool in_right_table = data.joined_columns.count(name);
bool in_left_table = data.left_table.hasColumn(name);
bool in_right_table = data.right_table.hasColumn(name);
if (in_left_table && in_right_table)
throw Exception("Column '" + name + "' is ambiguous", ErrorCodes::AMBIGUOUS_COLUMN_NAME);
{
/// Relax ambiguous check for multiple JOINs
if (auto original_name = IdentifierSemantic::uncover(*identifier))
{
auto match = IdentifierSemantic::canReferColumnToTable(*original_name, data.right_table.table);
if (match == IdentifierSemantic::ColumnMatch::NoMatch)
in_right_table = false;
in_left_table = !in_right_table;
}
else
throw Exception("Column '" + name + "' is ambiguous", ErrorCodes::AMBIGUOUS_COLUMN_NAME);
}
if (in_left_table)
membership = 1;

5
dbms/src/Interpreters/CollectJoinOnKeysVisitor.h
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@ -3,6 +3,7 @@
#include <Core/Names.h>
#include <Parsers/ASTFunction.h>
#include <Interpreters/InDepthNodeVisitor.h>
#include <Interpreters/DatabaseAndTableWithAlias.h>
#include <Interpreters/Aliases.h>
@ -25,8 +26,8 @@ public:
struct Data
{
AnalyzedJoin & analyzed_join;
const NameSet & source_columns;
const NameSet & joined_columns;
const TableWithColumnNames & left_table;
const TableWithColumnNames & right_table;
const Aliases & aliases;
const bool is_asof{false};
ASTPtr asof_left_key{};

14
dbms/src/Interpreters/DatabaseAndTableWithAlias.h
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@ -53,6 +53,20 @@ struct TableWithColumnNames
for (auto & column : addition)
hidden_columns.push_back(column.name);
}
bool hasColumn(const String & name) const
{
if (columns_set.empty())
{
columns_set.insert(columns.begin(), columns.end());
columns_set.insert(hidden_columns.begin(), hidden_columns.end());
}
return columns_set.count(name);
}
private:
mutable NameSet columns_set;
};
std::vector<DatabaseAndTableWithAlias> getDatabaseAndTables(const ASTSelectQuery & select_query, const String & current_database);

16
dbms/src/Interpreters/IdentifierSemantic.cpp
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@ -92,6 +92,22 @@ std::optional<String> IdentifierSemantic::getTableName(const ASTPtr & ast)
return {};
}
std::optional<ASTIdentifier> IdentifierSemantic::uncover(const ASTIdentifier & identifier)
{
if (identifier.semantic->covered)
{
std::vector<String> name_parts = identifier.name_parts;
return ASTIdentifier(std::move(name_parts));
}
return {};
}
void IdentifierSemantic::coverName(ASTIdentifier & identifier, const String & alias)
{
identifier.setShortName(alias);
identifier.semantic->covered = true;
}
bool IdentifierSemantic::canBeAlias(const ASTIdentifier & identifier)
{
return identifier.semantic->can_be_alias;

3
dbms/src/Interpreters/IdentifierSemantic.h
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@ -12,6 +12,7 @@ struct IdentifierSemanticImpl
{
bool special = false; /// for now it's 'not a column': tables, subselects and some special stuff like FORMAT
bool can_be_alias = true; /// if it's a cropped name it could not be an alias
bool covered = false; /// real (compound) name is hidden by an alias (short name)
std::optional<size_t> membership; /// table position in join
};
@ -43,6 +44,8 @@ struct IdentifierSemantic
static void setColumnLongName(ASTIdentifier & identifier, const DatabaseAndTableWithAlias & db_and_table);
static bool canBeAlias(const ASTIdentifier & identifier);
static void setMembership(ASTIdentifier &, size_t table_no);
static void coverName(ASTIdentifier &, const String & alias);
static std::optional<ASTIdentifier> uncover(const ASTIdentifier & identifier);
static std::optional<size_t> getMembership(const ASTIdentifier & identifier);
static bool chooseTable(const ASTIdentifier &, const std::vector<DatabaseAndTableWithAlias> & tables, size_t & best_table_pos,
bool ambiguous = false);

6
dbms/src/Interpreters/JoinToSubqueryTransformVisitor.cpp
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@ -159,7 +159,7 @@ struct ColumnAliasesMatcher
aliases[alias] = long_name;
rev_aliases[long_name].push_back(alias);
identifier->setShortName(alias);
IdentifierSemantic::coverName(*identifier, alias);
if (is_public)
{
identifier->setAlias(long_name);
@ -177,7 +177,7 @@ struct ColumnAliasesMatcher
if (is_public && allowed_long_names.count(long_name))
; /// leave original name unchanged for correct output
else
identifier->setShortName(it->second[0]);
IdentifierSemantic::coverName(*identifier, it->second[0]);
}
}
}
@ -229,7 +229,7 @@ struct ColumnAliasesMatcher
if (!last_table)
{
node.setShortName(alias);
IdentifierSemantic::coverName(node, alias);
node.setAlias("");
}
}

11
dbms/src/Interpreters/SyntaxAnalyzer.cpp
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@ -532,8 +532,8 @@ void setJoinStrictness(ASTSelectQuery & select_query, JoinStrictness join_defaul
}
/// Find the columns that are obtained by JOIN.
void collectJoinedColumns(AnalyzedJoin & analyzed_join, const ASTSelectQuery & select_query, const NameSet & source_columns,
const Aliases & aliases)
void collectJoinedColumns(AnalyzedJoin & analyzed_join, const ASTSelectQuery & select_query,
const std::vector<TableWithColumnNames> & tables, const Aliases & aliases)
{
const ASTTablesInSelectQueryElement * node = select_query.join();
if (!node)
@ -551,7 +551,7 @@ void collectJoinedColumns(AnalyzedJoin & analyzed_join, const ASTSelectQuery & s
{
bool is_asof = (table_join.strictness == ASTTableJoin::Strictness::Asof);
CollectJoinOnKeysVisitor::Data data{analyzed_join, source_columns, analyzed_join.getOriginalColumnsSet(), aliases, is_asof};
CollectJoinOnKeysVisitor::Data data{analyzed_join, tables[0], tables[1], aliases, is_asof};
CollectJoinOnKeysVisitor(data).visit(table_join.on_expression);
if (!data.has_some)
throw Exception("Cannot get JOIN keys from JOIN ON section: " + queryToString(table_join.on_expression),
@ -820,6 +820,7 @@ SyntaxAnalyzerResultPtr SyntaxAnalyzer::analyze(
if (storage)
collectSourceColumns(storage->getColumns(), result.source_columns, (select_query != nullptr));
NameSet source_columns_set = removeDuplicateColumns(result.source_columns);
std::vector<TableWithColumnNames> tables_with_columns;
if (select_query)
{
@ -837,7 +838,7 @@ SyntaxAnalyzerResultPtr SyntaxAnalyzer::analyze(
}
std::vector<const ASTTableExpression *> table_expressions = getTableExpressions(*select_query);
auto tables_with_columns = getTablesWithColumns(table_expressions, context);
tables_with_columns = getTablesWithColumns(table_expressions, context);
if (tables_with_columns.empty())
{
@ -935,7 +936,7 @@ SyntaxAnalyzerResultPtr SyntaxAnalyzer::analyze(
setJoinStrictness(*select_query, settings.join_default_strictness, settings.any_join_distinct_right_table_keys,
result.analyzed_join->table_join);
collectJoinedColumns(*result.analyzed_join, *select_query, source_columns_set, result.aliases);
collectJoinedColumns(*result.analyzed_join, *select_query, tables_with_columns, result.aliases);
}
result.aggregates = getAggregates(query);

0
dbms/tests/queries/0_stateless/01051_same_name_alias_with_joins.reference Normal file
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29
dbms/tests/queries/0_stateless/01051_same_name_alias_with_joins.sql Normal file
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@ -0,0 +1,29 @@
DROP TABLE IF EXISTS a;
DROP TABLE IF EXISTS b;
DROP TABLE IF EXISTS c;
CREATE TABLE a (x UInt64) ENGINE = Memory;
CREATE TABLE b (x UInt64) ENGINE = Memory;
CREATE TABLE c (x UInt64) ENGINE = Memory;
SET enable_optimize_predicate_expression = 0;
SELECT a.x AS x FROM a
LEFT JOIN b ON a.x = b.x
LEFT JOIN c ON a.x = c.x;
SELECT a.x AS x FROM a
LEFT JOIN b ON a.x = b.x
LEFT JOIN c ON b.x = c.x;
SELECT b.x AS x FROM a
LEFT JOIN b ON a.x = b.x
LEFT JOIN c ON b.x = c.x;
SELECT c.x AS x FROM a
LEFT JOIN b ON a.x = b.x
LEFT JOIN c ON b.x = c.x;
DROP TABLE a;
DROP TABLE b;
DROP TABLE c;