Allow multiple graph tables inside single query

src/duckpgq_extension.cpp

@@ -89,7 +89,7 @@ ParserExtensionParseResult duckpgq_parse(ParserExtensionInfo *info,
                                       : query);
   if (parser.statements.size() != 1) {
     throw Exception(ExceptionType::PARSER,
-        "More than 1 statement detected, please only give one.");
+        "More than one statement detected, please only give one.");
   }
   return ParserExtensionParseResult(make_uniq_base<ParserExtensionParseData, DuckPGQParseData>(
       std::move(parser.statements[0])));
@@ -119,15 +119,11 @@ void duckpgq_find_match_function(TableRef *table_ref,
     // Handle TableFunctionRef case
     auto function =
         dynamic_cast<FunctionExpression *>(table_function_ref->function.get());
-    if (function->function_name == "duckpgq_match") {
-      if (duckpgq_state.transform_expression != nullptr) {
-        throw Exception(ExceptionType::INVALID,
-                        "Multiple graph tables in a single query are not supported yet");
-      }
-      duckpgq_state.transform_expression =
-          std::move(std::move(function->children[0]));
-      function->children.pop_back();
+    if (function->function_name != "duckpgq_match") {
+      return;
     }
+    duckpgq_state.transform_expression.push_back(std::move(function->children[0]));
+    function->children.pop_back();
   } else if (auto join_ref = dynamic_cast<JoinRef *>(table_ref)) {
     // Handle JoinRef case
     duckpgq_find_match_function(join_ref->left.get(), duckpgq_state);

src/functions/tablefunctions/match.cpp

@@ -943,11 +943,9 @@ PGQMatchFunction::MatchBindReplace(ClientContext &context,
       dynamic_cast<DuckPGQState *>(duckpgq_state_entry->second.get());
 
   auto ref = dynamic_cast<MatchExpression *>(
-      duckpgq_state->transform_expression.get());
+      duckpgq_state->transform_expression[0].get());
   auto pg_table = duckpgq_state->GetPropertyGraph(ref->pg_name);
 
-  auto data = make_uniq<MatchBindData>();
-
   vector<unique_ptr<ParsedExpression>> conditions;
 
   auto select_node = make_uniq<SelectNode>();
@@ -1040,8 +1038,16 @@ PGQMatchFunction::MatchBindReplace(ClientContext &context,
 
   auto subquery = make_uniq<SelectStatement>();
   subquery->node = std::move(select_node);
+  if (ref->alias == "unnamed_graphtable") {
+    if (duckpgq_state->unnamed_graphtable_index > 1) {
+      ref->alias = "unnamed_graphtable" +
+                   std::to_string(duckpgq_state->unnamed_graphtable_index);
+    }
+    duckpgq_state->unnamed_graphtable_index++;
+  }
 
   auto result = make_uniq<SubqueryRef>(std::move(subquery), ref->alias);
+  duckpgq_state->transform_expression.erase(duckpgq_state->transform_expression.begin());
   return std::move(result);
 }
 } // namespace duckdb

src/include/duckpgq_extension.hpp

@@ -79,7 +79,8 @@ class DuckPGQState : public ClientContextState {
 
   void QueryEnd() override {
     parse_data.reset();
-    transform_expression = nullptr;
+    transform_expression.clear();
+    unnamed_graphtable_index = 1; // Reset the index
     for (const auto &csr_id : csr_to_delete) {
       csr_list.erase(csr_id);
     }
@@ -105,7 +106,10 @@ class DuckPGQState : public ClientContextState {
 public:
   unique_ptr<ParserExtensionParseData> parse_data;
 
-  unique_ptr<ParsedExpression> transform_expression;
+  vector<unique_ptr<ParsedExpression>> transform_expression;
+
+  int32_t unnamed_graphtable_index = 1; // Used to generate unique names for
+                                        // unnamed graph tables
 
   //! Property graphs that are registered
   std::unordered_map<string, unique_ptr<CreateInfo>> registered_property_graphs;

test/sql/multiple_graph_table.test

@@ -0,0 +1,171 @@
+# name: test/sql/multiple_graph_table.test
+# group: [duckpgq]
+
+require duckpgq
+
+statement ok
+CREATE TABLE Student(id BIGINT, name VARCHAR);INSERT INTO Student VALUES (0, 'Daniel'), (1, 'Tavneet'), (2, 'Gabor'), (3, 'Peter'), (4, 'David');
+
+statement ok
+CREATE TABLE know(src BIGINT, dst BIGINT, createDate BIGINT);INSERT INTO know VALUES (0,1, 10), (0,2, 11), (0,3, 12), (3,0, 13), (1,2, 14), (1,3, 15), (2,3, 16), (4,3, 17);
+
+statement ok
+CREATE TABLE School(name VARCHAR, Id BIGINT, Kind VARCHAR);INSERT INTO School VALUES ('VU', 0, 'University'), ('UVA', 1, 'University');
+
+statement ok
+CREATE TABLE StudyAt(personId BIGINT, schoolId BIGINT);INSERT INTO StudyAt VALUES (0, 0), (1, 0), (2, 1), (3, 1), (4, 1);
+
+statement ok
+-CREATE PROPERTY GRAPH pg
+VERTEX TABLES (
+    Student,
+    School
+    )
+EDGE TABLES (
+    know    SOURCE KEY ( src ) REFERENCES Student ( id )
+            DESTINATION KEY ( dst ) REFERENCES Student ( id ),
+    studyAt SOURCE KEY ( personId ) REFERENCES Student ( id )
+            DESTINATION KEY ( SchoolId ) REFERENCES School ( id )
+    );
+
+query II
+-select a.id, b.id FROM GRAPH_TABLE(pg MATCH (a:student)) a, GRAPH_TABLE(pg MATCH (b:student)) b;
+----
+0	0
+0	1
+0	2
+0	3
+0	4
+1	0
+1	1
+1	2
+1	3
+1	4
+2	0
+2	1
+2	2
+2	3
+2	4
+3	0
+3	1
+3	2
+3	3
+3	4
+4	0
+4	1
+4	2
+4	3
+4	4
+
+query II
+-select unnamed_graphtable.id, unnamed_graphtable2.id FROM GRAPH_TABLE(pg MATCH (a:student)), GRAPH_TABLE(pg MATCH (b:student));
+----
+0	0
+0	1
+0	2
+0	3
+0	4
+1	0
+1	1
+1	2
+1	3
+1	4
+2	0
+2	1
+2	2
+2	3
+2	4
+3	0
+3	1
+3	2
+3	3
+3	4
+4	0
+4	1
+4	2
+4	3
+4	4
+
+
+query IIII
+-select a.id, a.name, unnamed_graphtable.id, unnamed_graphtable.name FROM GRAPH_TABLE(pg MATCH (a:student)) a, GRAPH_TABLE(pg MATCH (b:student)-[r:know]->(c:student));
+----
+0	Daniel	1	Tavneet
+0	Daniel	2	Gabor
+0	Daniel	3	Peter
+0	Daniel	0	Daniel
+0	Daniel	2	Gabor
+0	Daniel	3	Peter
+0	Daniel	3	Peter
+0	Daniel	3	Peter
+1	Tavneet	1	Tavneet
+1	Tavneet	2	Gabor
+1	Tavneet	3	Peter
+1	Tavneet	0	Daniel
+1	Tavneet	2	Gabor
+1	Tavneet	3	Peter
+1	Tavneet	3	Peter
+1	Tavneet	3	Peter
+2	Gabor	1	Tavneet
+2	Gabor	2	Gabor
+2	Gabor	3	Peter
+2	Gabor	0	Daniel
+2	Gabor	2	Gabor
+2	Gabor	3	Peter
+2	Gabor	3	Peter
+2	Gabor	3	Peter
+3	Peter	1	Tavneet
+3	Peter	2	Gabor
+3	Peter	3	Peter
+3	Peter	0	Daniel
+3	Peter	2	Gabor
+3	Peter	3	Peter
+3	Peter	3	Peter
+3	Peter	3	Peter
+4	David	1	Tavneet
+4	David	2	Gabor
+4	David	3	Peter
+4	David	0	Daniel
+4	David	2	Gabor
+4	David	3	Peter
+4	David	3	Peter
+4	David	3	Peter
+
+
+query II
+-select unnamed_subquery.id, unnamed_graphtable.id
+FROM GRAPH_TABLE(pg MATCH (a:student)), (select 1 as id);
+----
+1	0
+1	1
+1	2
+1	3
+1	4
+
+statement ok
+CREATE TABLE cities (
+name VARCHAR,
+lat DECIMAL,
+lon DECIMAL
+);
+
+statement ok
+CREATE TABLE cities_are_adjacent (
+city1name VARCHAR,
+city2name VARCHAR
+);
+
+statement ok
+-CREATE PROPERTY GRAPH citymap
+VERTEX TABLES (
+cities PROPERTIES (name,lat,lon) LABEL city
+)
+EDGE TABLES (
+cities_are_adjacent SOURCE KEY ( city1name ) REFERENCES cities ( name )
+DESTINATION KEY ( city2name ) REFERENCES cities ( name )
+LABEL adjacent
+);
+
+statement ok
+-select * from GRAPH_TABLE (citymap MATCH (s:city)-[r:adjacent]->(t:city)) g1, GRAPH_TABLE (citymap MATCH (s:city)-[r:adjacent]->(t:city)) g2;
+