support ASOF JOIN ON syntax

This commit is contained in:
chertus 2019-07-29 17:58:36 +03:00
parent c4f1038efc
commit 7b4ddd268e
6 changed files with 267 additions and 151 deletions

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@ -0,0 +1,210 @@
#include <Parsers/queryToString.h>
#include <Interpreters/CollectJoinOnKeysVisitor.h>
#include <Interpreters/IdentifierSemantic.h>
#include <Interpreters/AnalyzedJoin.h>
namespace DB
{
namespace ErrorCodes
{
extern const int INVALID_JOIN_ON_EXPRESSION;
extern const int AMBIGUOUS_COLUMN_NAME;
extern const int NOT_IMPLEMENTED;
extern const int LOGICAL_ERROR;
}
void CollectJoinOnKeysMatcher::Data::addJoinKeys(const ASTPtr & left_ast, const ASTPtr & right_ast,
const std::pair<size_t, size_t> & table_no)
{
ASTPtr left = left_ast->clone();
ASTPtr right = right_ast->clone();
if (table_no.first == 1 || table_no.second == 2)
analyzed_join.addOnKeys(left, right);
else if (table_no.first == 2 || table_no.second == 1)
analyzed_join.addOnKeys(right, left);
else
throw Exception("Cannot detect left and right JOIN keys. JOIN ON section is ambiguous.",
ErrorCodes::AMBIGUOUS_COLUMN_NAME);
has_some = true;
}
void CollectJoinOnKeysMatcher::Data::addAsofJoinKeys(const ASTPtr & left_ast, const ASTPtr & right_ast,
const std::pair<size_t, size_t> & table_no)
{
if (table_no.first == 1 || table_no.second == 2)
{
asof_left_key = left_ast->clone();
asof_right_key = right_ast->clone();
return;
}
throw Exception("ASOF JOIN for (left_table.x <= right_table.x) is not implemented", ErrorCodes::NOT_IMPLEMENTED);
}
void CollectJoinOnKeysMatcher::Data::asofToJoinKeys()
{
if (!asof_left_key || !asof_right_key)
throw Exception("No inequality in ASOF JOIN ON section.", ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
addJoinKeys(asof_left_key, asof_right_key, {1, 2});
}
void CollectJoinOnKeysMatcher::visit(const ASTFunction & func, const ASTPtr & ast, Data & data)
{
if (func.name == "and")
return; /// go into children
if (func.name == "equals")
{
ASTPtr left = func.arguments->children.at(0);
ASTPtr right = func.arguments->children.at(1);
auto table_numbers = getTableNumbers(ast, left, right, data);
data.addJoinKeys(left, right, table_numbers);
return;
}
bool less_or_equals = (func.name == "lessOrEquals");
bool greater_or_equals = (func.name == "greaterOrEquals");
if (data.is_asof && (less_or_equals || greater_or_equals))
{
if (data.asof_left_key || data.asof_right_key)
throwSyntaxException("ASOF JOIN expects exactly one inequality in ON section, unexpected " + queryToString(ast) + ".");
ASTPtr left = func.arguments->children.at(0);
ASTPtr right = func.arguments->children.at(1);
auto table_numbers = getTableNumbers(ast, left, right, data);
if (greater_or_equals)
data.addAsofJoinKeys(left, right, table_numbers);
else
data.addAsofJoinKeys(right, left, std::make_pair(table_numbers.second, table_numbers.first));
return;
}
throwSyntaxException("Expected equals expression, got " + queryToString(ast) + ".");
}
void CollectJoinOnKeysMatcher::getIdentifiers(const ASTPtr & ast, std::vector<const ASTIdentifier *> & out)
{
if (const auto * ident = ast->as<ASTIdentifier>())
{
if (IdentifierSemantic::getColumnName(*ident))
out.push_back(ident);
return;
}
for (const auto & child : ast->children)
getIdentifiers(child, out);
}
std::pair<size_t, size_t> CollectJoinOnKeysMatcher::getTableNumbers(const ASTPtr & expr, const ASTPtr & left_ast, const ASTPtr & right_ast,
Data & data)
{
std::vector<const ASTIdentifier *> left_identifiers;
std::vector<const ASTIdentifier *> right_identifiers;
getIdentifiers(left_ast, left_identifiers);
getIdentifiers(right_ast, right_identifiers);
size_t left_idents_table = getTableForIdentifiers(left_identifiers, data);
size_t right_idents_table = getTableForIdentifiers(right_identifiers, data);
if (left_idents_table && left_idents_table == right_idents_table)
{
auto left_name = queryToString(*left_identifiers[0]);
auto right_name = queryToString(*right_identifiers[0]);
throwSyntaxException("In expression " + queryToString(expr) + " columns " + left_name + " and " + right_name
+ " are from the same table but from different arguments of equal function.");
}
return std::make_pair(left_idents_table, right_idents_table);
}
const ASTIdentifier * CollectJoinOnKeysMatcher::unrollAliases(const ASTIdentifier * identifier, const Aliases & aliases)
{
if (identifier->compound())
return identifier;
UInt32 max_attempts = 100;
for (auto it = aliases.find(identifier->name); it != aliases.end();)
{
const ASTIdentifier * parent = identifier;
identifier = it->second->as<ASTIdentifier>();
if (!identifier)
break; /// not a column alias
if (identifier == parent)
break; /// alias to itself with the same name: 'a as a'
if (identifier->compound())
break; /// not an alias. Break to prevent cycle through short names: 'a as b, t1.b as a'
it = aliases.find(identifier->name);
if (!max_attempts--)
throw Exception("Cannot unroll aliases for '" + identifier->name + "'", ErrorCodes::LOGICAL_ERROR);
}
return identifier;
}
/// @returns 1 if identifiers belongs to left table, 2 for right table and 0 if unknown. Throws on table mix.
/// Place detected identifier into identifiers[0] if any.
size_t CollectJoinOnKeysMatcher::getTableForIdentifiers(std::vector<const ASTIdentifier *> & identifiers, const Data & data)
{
size_t table_number = 0;
for (auto & ident : identifiers)
{
const ASTIdentifier * identifier = unrollAliases(ident, data.aliases);
if (!identifier)
continue;
/// Column name could be cropped to a short form in TranslateQualifiedNamesVisitor.
/// In this case it saves membership in IdentifierSemantic.
size_t membership = IdentifierSemantic::getMembership(*identifier);
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);
if (in_left_table && in_right_table)
throw Exception("Column '" + name + "' is ambiguous", ErrorCodes::AMBIGUOUS_COLUMN_NAME);
if (in_left_table)
membership = 1;
if (in_right_table)
membership = 2;
}
if (membership && table_number == 0)
{
table_number = membership;
std::swap(ident, identifiers[0]); /// move first detected identifier to the first position
}
if (membership && membership != table_number)
{
throw Exception("Invalid columns in JOIN ON section. Columns "
+ identifiers[0]->getAliasOrColumnName() + " and " + ident->getAliasOrColumnName()
+ " are from different tables.", ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
}
}
return table_number;
}
[[noreturn]] void CollectJoinOnKeysMatcher::throwSyntaxException(const String & msg)
{
throw Exception("Invalid expression for JOIN ON. " + msg +
" Supported syntax: JOIN ON Expr([table.]column, ...) = Expr([table.]column, ...) "
"[AND Expr([table.]column, ...) = Expr([table.]column, ...) ...]",
ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
}
}

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@ -1,23 +1,16 @@
#pragma once
#include <Core/Names.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/queryToString.h>
#include <Interpreters/InDepthNodeVisitor.h>
#include <Interpreters/Aliases.h>
#include <Interpreters/SyntaxAnalyzer.h>
namespace DB
{
namespace ErrorCodes
{
extern const int INVALID_JOIN_ON_EXPRESSION;
extern const int AMBIGUOUS_COLUMN_NAME;
extern const int LOGICAL_ERROR;
}
class ASTIdentifier;
struct AnalyzedJoin;
class CollectJoinOnKeysMatcher
{
@ -30,7 +23,14 @@ public:
const NameSet & source_columns;
const NameSet & joined_columns;
const Aliases & aliases;
bool has_some = false;
const bool is_asof;
ASTPtr asof_left_key{};
ASTPtr asof_right_key{};
bool has_some{false};
void addJoinKeys(const ASTPtr & left_ast, const ASTPtr & right_ast, const std::pair<size_t, size_t> & table_no);
void addAsofJoinKeys(const ASTPtr & left_ast, const ASTPtr & right_ast, const std::pair<size_t, size_t> & table_no);
void asofToJoinKeys();
};
static void visit(const ASTPtr & ast, Data & data)
@ -48,146 +48,14 @@ public:
}
private:
static void visit(const ASTFunction & func, const ASTPtr & ast, Data & data)
{
if (func.name == "and")
return; /// go into children
static void visit(const ASTFunction & func, const ASTPtr & ast, Data & data);
if (func.name == "equals")
{
ASTPtr left = func.arguments->children.at(0)->clone();
ASTPtr right = func.arguments->children.at(1)->clone();
addJoinKeys(ast, left, right, data);
return;
}
static void getIdentifiers(const ASTPtr & ast, std::vector<const ASTIdentifier *> & out);
static std::pair<size_t, size_t> getTableNumbers(const ASTPtr & expr, const ASTPtr & left_ast, const ASTPtr & right_ast, Data & data);
static const ASTIdentifier * unrollAliases(const ASTIdentifier * identifier, const Aliases & aliases);
static size_t getTableForIdentifiers(std::vector<const ASTIdentifier *> & identifiers, const Data & data);
throwSyntaxException("Expected equals expression, got " + queryToString(ast) + ".");
}
static void getIdentifiers(const ASTPtr & ast, std::vector<const ASTIdentifier *> & out)
{
if (const auto * ident = ast->as<ASTIdentifier>())
{
if (IdentifierSemantic::getColumnName(*ident))
out.push_back(ident);
return;
}
for (const auto & child : ast->children)
getIdentifiers(child, out);
}
static void addJoinKeys(const ASTPtr & expr, ASTPtr left_ast, ASTPtr right_ast, Data & data)
{
std::vector<const ASTIdentifier *> left_identifiers;
std::vector<const ASTIdentifier *> right_identifiers;
getIdentifiers(left_ast, left_identifiers);
getIdentifiers(right_ast, right_identifiers);
size_t left_idents_table = getTableForIdentifiers(left_identifiers, data);
size_t right_idents_table = getTableForIdentifiers(right_identifiers, data);
if (left_idents_table && left_idents_table == right_idents_table)
{
auto left_name = queryToString(*left_identifiers[0]);
auto right_name = queryToString(*right_identifiers[0]);
throwSyntaxException("In expression " + queryToString(expr) + " columns " + left_name + " and " + right_name
+ " are from the same table but from different arguments of equal function.");
}
if (left_idents_table == 1 || right_idents_table == 2)
data.analyzed_join.addOnKeys(left_ast, right_ast);
else if (left_idents_table == 2 || right_idents_table == 1)
data.analyzed_join.addOnKeys(right_ast, left_ast);
else
throw Exception("Cannot detect left and right JOIN keys. JOIN ON section is ambiguous.",
ErrorCodes::AMBIGUOUS_COLUMN_NAME);
data.has_some = true;
}
static const ASTIdentifier * unrollAliases(const ASTIdentifier * identifier, const Aliases & aliases)
{
if (identifier->compound())
return identifier;
UInt32 max_attempts = 100;
for (auto it = aliases.find(identifier->name); it != aliases.end();)
{
const ASTIdentifier * parent = identifier;
identifier = it->second->as<ASTIdentifier>();
if (!identifier)
break; /// not a column alias
if (identifier == parent)
break; /// alias to itself with the same name: 'a as a'
if (identifier->compound())
break; /// not an alias. Break to prevent cycle through short names: 'a as b, t1.b as a'
it = aliases.find(identifier->name);
if (!max_attempts--)
throw Exception("Cannot unroll aliases for '" + identifier->name + "'", ErrorCodes::LOGICAL_ERROR);
}
return identifier;
}
/// @returns 1 if identifiers belongs to left table, 2 for right table and 0 if unknown. Throws on table mix.
/// Place detected identifier into identifiers[0] if any.
static size_t getTableForIdentifiers(std::vector<const ASTIdentifier *> & identifiers, const Data & data)
{
size_t table_number = 0;
for (auto & ident : identifiers)
{
const ASTIdentifier * identifier = unrollAliases(ident, data.aliases);
if (!identifier)
continue;
/// Column name could be cropped to a short form in TranslateQualifiedNamesVisitor.
/// In this case it saves membership in IdentifierSemantic.
size_t membership = IdentifierSemantic::getMembership(*identifier);
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);
if (in_left_table && in_right_table)
throw Exception("Column '" + name + "' is ambiguous", ErrorCodes::AMBIGUOUS_COLUMN_NAME);
if (in_left_table)
membership = 1;
if (in_right_table)
membership = 2;
}
if (membership && table_number == 0)
{
table_number = membership;
std::swap(ident, identifiers[0]); /// move first detected identifier to the first position
}
if (membership && membership != table_number)
{
throw Exception("Invalid columns in JOIN ON section. Columns "
+ identifiers[0]->getAliasOrColumnName() + " and " + ident->getAliasOrColumnName()
+ " are from different tables.", ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
}
}
return table_number;
}
[[noreturn]] static void throwSyntaxException(const String & msg)
{
throw Exception("Invalid expression for JOIN ON. " + msg +
" Supported syntax: JOIN ON Expr([table.]column, ...) = Expr([table.]column, ...) "
"[AND Expr([table.]column, ...) = Expr([table.]column, ...) ...]",
ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
}
[[noreturn]] static void throwSyntaxException(const String & msg);
};
/// Parse JOIN ON expression and collect ASTs for joined columns.

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@ -22,6 +22,7 @@
#include <Parsers/ASTTablesInSelectQuery.h>
#include <Parsers/ParserTablesInSelectQuery.h>
#include <Parsers/parseQuery.h>
#include <Parsers/queryToString.h>
#include <DataTypes/NestedUtils.h>
@ -509,11 +510,14 @@ void collectJoinedColumns(AnalyzedJoin & analyzed_join, const ASTSelectQuery & s
for (const auto & col : analyzed_join.columns_from_joined_table)
joined_columns.insert(col.original_name);
CollectJoinOnKeysVisitor::Data data{analyzed_join, source_columns, joined_columns, aliases};
bool is_asof = (table_join.strictness == ASTTableJoin::Strictness::Asof);
CollectJoinOnKeysVisitor::Data data{analyzed_join, source_columns, joined_columns, 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),
ErrorCodes::INVALID_JOIN_ON_EXPRESSION);
if (is_asof)
data.asofToJoinKeys();
}
bool make_nullable = join_use_nulls && isLeftOrFull(table_join.kind);

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@ -12,7 +12,7 @@ INSERT INTO B(k,t,b) VALUES (2,3,3);
SELECT A.k, toString(A.t, 'UTC'), A.a, B.b, toString(B.t, 'UTC'), B.k FROM A ASOF LEFT JOIN B USING(k,t) ORDER BY (A.k, A.t);
SELECT A.k, toString(A.t, 'UTC'), A.a, B.b, toString(B.t, 'UTC'), B.k FROM A ASOF INNER JOIN B ON A.k == B.k AND A.t == B.t ORDER BY (A.k, A.t);
SELECT A.k, toString(A.t, 'UTC'), A.a, B.b, toString(B.t, 'UTC'), B.k FROM A ASOF INNER JOIN B ON A.k == B.k AND A.t >= B.t ORDER BY (A.k, A.t);
SELECT A.k, toString(A.t, 'UTC'), A.a, B.b, toString(B.t, 'UTC'), B.k FROM A ASOF JOIN B USING(k,t) ORDER BY (A.k, A.t);

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@ -0,0 +1,13 @@
1 1 0 0
1 2 1 2
1 3 1 2
2 1 0 0
2 2 0 0
2 3 2 3
3 1 0 0
3 2 0 0
3 3 0 0
9
1 2 1 2
1 3 1 2
2 3 2 3

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@ -0,0 +1,21 @@
DROP TABLE IF EXISTS A;
DROP TABLE IF EXISTS B;
CREATE TABLE A(a UInt32, t UInt32) ENGINE = Memory;
CREATE TABLE B(b UInt32, t UInt32) ENGINE = Memory;
INSERT INTO A (a,t) VALUES (1,1),(1,2),(1,3), (2,1),(2,2),(2,3), (3,1),(3,2),(3,3);
INSERT INTO B (b,t) VALUES (1,2),(1,4),(2,3);
SELECT A.a, A.t, B.b, B.t FROM A ASOF LEFT JOIN B ON A.a == B.b AND A.t >= B.t ORDER BY (A.a, A.t);
SELECT count() FROM A ASOF LEFT JOIN B ON A.a == B.b AND B.t <= A.t;
SELECT A.a, A.t, B.b, B.t FROM A ASOF INNER JOIN B ON B.t <= A.t AND A.a == B.b;
SELECT count() FROM A ASOF JOIN B ON A.a == B.b AND A.t <= B.t; -- { serverError 48 }
SELECT count() FROM A ASOF JOIN B ON A.a == B.b AND B.t >= A.t; -- { serverError 48 }
SELECT count() FROM A ASOF JOIN B ON A.a == B.b AND A.t > B.t; -- { serverError 403 }
SELECT count() FROM A ASOF JOIN B ON A.a == B.b AND A.t < B.t; -- { serverError 403 }
SELECT count() FROM A ASOF JOIN B ON A.a == B.b AND A.t == B.t; -- { serverError 403 }
SELECT count() FROM A ASOF JOIN B ON A.a == B.b AND A.t != B.t; -- { serverError 403 }
DROP TABLE A;
DROP TABLE B;