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ClickHouse: fixed ARRAY JOIN when its result is unused. [#CONV-8821]

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This commit is contained in:
Michael Kolupaev 2013-10-18 08:40:14 +00:00
parent 59b80197fc
commit bc071d70c1
1 changed files with 50 additions and 20 deletions
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70
dbms/src/Interpreters/ExpressionAnalyzer.cpp
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@ -662,6 +662,35 @@ void ExpressionAnalyzer::getArrayJoinedColumns()
getArrayJoinedColumnsImpl(select_query->where_expression);
getArrayJoinedColumnsImpl(select_query->having_expression);
getArrayJoinedColumnsImpl(select_query->order_expression_list);
/// Если результат ARRAY JOIN не используется, придется все равно по-ARRAY-JOIN-ить какой-нибудь столбец,
/// чтобы получить правильное количество строк.
if (columns_for_array_join.empty())
{
ASTPtr expr = select_query->array_join_expression_list->children[0];
String source_name = expr->getColumnName();
String result_name = expr->getAlias();
/// Это массив.
if (!dynamic_cast<ASTIdentifier *>(&*expr) || findColumn(source_name, columns) != columns.end())
{
columns_for_array_join.insert(result_name);
}
else /// Это вложенная таблица.
{
bool found = false;
for (NamesAndTypesList::iterator it = columns.begin(); it != columns.end(); ++it)
{
String table_name = DataTypeNested::extractNestedTableName(it->first);
String column_name = DataTypeNested::extractNestedColumnName(it->first);
if (table_name == source_name)
{
columns_for_array_join.insert(DataTypeNested::concatenateNestedName(result_name, column_name));
found = true;
break;
}
}
}
}
}
}
@ -990,9 +1019,8 @@ void ExpressionAnalyzer::initChain(ExpressionActionsChain & chain, NamesAndTypes
void ExpressionAnalyzer::addMultipleArrayJoinAction(ExpressionActions & actions)
{
ASTs & asts = select_query->array_join_expression_list->children;
typedef std::map<String, String> NameToAlias;
NameToAlias name_to_alias;
NameSet known_aliases;
typedef std::map<String, String> AliasToName;
AliasToName alias_to_name;
for (size_t i = 0; i < asts.size(); ++i)
{
ASTPtr ast = asts[i];
@ -1002,31 +1030,33 @@ void ExpressionAnalyzer::addMultipleArrayJoinAction(ExpressionActions & actions)
if (nested_table_alias == nested_table_name && !dynamic_cast<ASTIdentifier *>(&*ast))
throw Exception("No alias for non-trivial value in ARRAY JOIN: " + nested_table_name, ErrorCodes::ALIAS_REQUIRED);
if (known_aliases.count(nested_table_alias) || aliases.count(nested_table_alias))
if (alias_to_name.count(nested_table_alias) || aliases.count(nested_table_alias))
throw Exception("Duplicate alias " + nested_table_alias, ErrorCodes::MULTIPLE_EXPRESSIONS_FOR_ALIAS);
if (name_to_alias.count(nested_table_name))
throw Exception("Duplicate ARRAY JOIN on column " + nested_table_name, ErrorCodes::MULTIPLE_EXPRESSIONS_FOR_ALIAS);
known_aliases.insert(nested_table_alias);
name_to_alias[nested_table_name] = nested_table_alias;
alias_to_name[nested_table_alias] = nested_table_name;
}
NamesAndTypesList input_columns = actions.getSampleBlock().getColumnsList();
for (NamesAndTypesList::const_iterator it = input_columns.begin(); it != input_columns.end(); ++it)
for (NamesSet::iterator it = columns_for_array_join.begin(); it != columns_for_array_join.end(); ++it)
{
const String & name = it->first;
const String & result_name = *it;
String nested_table = DataTypeNested::extractNestedTableName(name);
String nested_column = DataTypeNested::extractNestedColumnName(name);
String result_table = DataTypeNested::extractNestedTableName(result_name);
String result_column = DataTypeNested::extractNestedColumnName(result_name);
String array_joined_name;
if (name_to_alias.count(name))
array_joined_name = name_to_alias[name];
else if (name_to_alias.count(nested_table))
array_joined_name = DataTypeNested::concatenateNestedName(name_to_alias[nested_table], nested_column);
String source_name;
if (alias_to_name.count(result_name))
{
source_name = alias_to_name[result_name];
}
else if (alias_to_name.count(result_table))
{
source_name = DataTypeNested::concatenateNestedName(alias_to_name[result_table], result_column);
}
else
continue;
{
throw Exception("Unexpected result of ARRAY JOIN", ErrorCodes::LOGICAL_ERROR);
}
actions.add(ExpressionActions::Action::copyColumn(name, array_joined_name));
actions.add(ExpressionActions::Action::copyColumn(source_name, result_name));
}
actions.add(ExpressionActions::Action::arrayJoin(columns_for_array_join));