From 7fff89e9c06b799c1f9f651b613b8d4306d4e584 Mon Sep 17 00:00:00 2001
From: Chen22 <jingchen2222@gmail.com>
Date: Thu, 13 May 2021 11:57:54 -0700
Subject: [PATCH 1/3] feat: support last join 1. change LAST as reserved
 keyword 2. change keywords_test ut 3. add LAST JOIN test cases

---
 zetasql/parser/bison_parser.y        |  5 +-
 zetasql/parser/keywords.cc           |  2 +-
 zetasql/parser/keywords_test.cc      |  2 +-
 zetasql/parser/parse_tree.cc         |  2 +
 zetasql/parser/parse_tree_manual.h   |  2 +-
 zetasql/parser/testdata/from.test    | 83 +++++++++++++++++++++++++++-
 zetasql/parser/testdata/orderby.test | 18 +++---
 7 files changed, 99 insertions(+), 15 deletions(-)

diff --git a/zetasql/parser/bison_parser.y b/zetasql/parser/bison_parser.y
index 20c206567..3c0b112f5 100644
--- a/zetasql/parser/bison_parser.y
+++ b/zetasql/parser/bison_parser.y
@@ -703,6 +703,7 @@ using zetasql::ASTDropStatement;
 %token KW_INTO "INTO"
 %token KW_IS "IS"
 %token KW_JOIN "JOIN"
+%token KW_LAST "LAST"
 %token KW_LEFT "LEFT"
 %token KW_LIKE "LIKE"
 %token KW_LIMIT "LIMIT"
@@ -842,7 +843,6 @@ using zetasql::ASTDropStatement;
 %token KW_JSON "JSON"
 %token KW_KEY "KEY"
 %token KW_LANGUAGE "LANGUAGE"
-%token KW_LAST "LAST"
 %token KW_LEAVE "LEAVE"
 %token KW_LEVEL "LEVEL"
 %token KW_LOOP "LOOP"
@@ -4631,6 +4631,7 @@ join_type:
     | "INNER" { $$ = zetasql::ASTJoin::INNER; }
     | "LEFT" opt_outer { $$ = zetasql::ASTJoin::LEFT; }
     | "RIGHT" opt_outer { $$ = zetasql::ASTJoin::RIGHT; }
+    | "LAST" { $$ = zetasql::ASTJoin::LAST; }
     | /* Nothing */  { $$ = zetasql::ASTJoin::DEFAULT_JOIN_TYPE; }
     ;
 
@@ -7036,6 +7037,7 @@ reserved_keyword_rule:
     | "INTO"
     | "IS"
     | "JOIN"
+    | "LAST"
     | "LEFT"
     | "LIKE"
     | "LIMIT"
@@ -7171,7 +7173,6 @@ keyword_as_identifier:
     | "JSON"
     | "KEY"
     | "LANGUAGE"
-    | "LAST"
     | "LEAVE"
     | "LEVEL"
     | "LOOP"
diff --git a/zetasql/parser/keywords.cc b/zetasql/parser/keywords.cc
index b9a3f9ea1..6eb2b7834 100644
--- a/zetasql/parser/keywords.cc
+++ b/zetasql/parser/keywords.cc
@@ -173,7 +173,7 @@ constexpr KeywordInfoPOD kAllKeywords[] = {
     {"json", KW_JSON},
     {"key", KW_KEY},
     {"language", KW_LANGUAGE},
-    {"last", KW_LAST},
+    {"last", KW_LAST, KeywordInfo::kReserved},
     {"lateral", KW_LATERAL, KeywordInfo::kReserved},
     {"leave", KW_LEAVE},
     {"left", KW_LEFT, KeywordInfo::kReserved},
diff --git a/zetasql/parser/keywords_test.cc b/zetasql/parser/keywords_test.cc
index f71129ea6..16e9a5247 100644
--- a/zetasql/parser/keywords_test.cc
+++ b/zetasql/parser/keywords_test.cc
@@ -237,7 +237,7 @@ TEST(ParserTest, DontAddNewReservedKeywords) {
   // allows new queries to work that will not work on older code.
   // Before changing this, co-ordinate with all engines to make sure the change
   // is done safely.
-  EXPECT_EQ(97 /* CAUTION */, num_reserved);
+  EXPECT_EQ(98 /* CAUTION */, num_reserved);
 }
 
 }  // namespace
diff --git a/zetasql/parser/parse_tree.cc b/zetasql/parser/parse_tree.cc
index dd48240cc..192a048f9 100644
--- a/zetasql/parser/parse_tree.cc
+++ b/zetasql/parser/parse_tree.cc
@@ -649,6 +649,8 @@ std::string ASTJoin::GetSQLForJoinType() const {
       return "LEFT";
     case RIGHT:
       return "RIGHT";
+    case LAST:
+      return "LAST";
   }
 }
 
diff --git a/zetasql/parser/parse_tree_manual.h b/zetasql/parser/parse_tree_manual.h
index e656c623d..177644486 100644
--- a/zetasql/parser/parse_tree_manual.h
+++ b/zetasql/parser/parse_tree_manual.h
@@ -1286,7 +1286,7 @@ class ASTJoin final : public ASTTableExpression {
   std::string GetSQLForJoinType() const;
   std::string GetSQLForJoinHint() const;
 
-  enum JoinType { DEFAULT_JOIN_TYPE, COMMA, CROSS, FULL, INNER, LEFT, RIGHT };
+  enum JoinType { DEFAULT_JOIN_TYPE, COMMA, CROSS, FULL, INNER, LEFT, RIGHT, LAST};
 
   JoinType join_type() const { return join_type_; }
   void set_join_type(JoinType join_type) { join_type_ = join_type; }
diff --git a/zetasql/parser/testdata/from.test b/zetasql/parser/testdata/from.test
index 82b2b0dca..6038f20ec 100644
--- a/zetasql/parser/testdata/from.test
+++ b/zetasql/parser/testdata/from.test
@@ -90,6 +90,50 @@ FROM
   USING(c, d)
 ==
 
+select T1.a as a, T2.b as b from Table1 as T1 last join Table2 T2 using (c, d);
+--
+QueryStatement [0-78]
+  Query [0-78]
+    Select [0-78]
+      SelectList [7-27]
+        SelectColumn [7-16]
+          PathExpression [7-11]
+            Identifier(T1) [7-9]
+            Identifier(a) [10-11]
+          Alias [12-16]
+            Identifier(a) [15-16]
+        SelectColumn [18-27]
+          PathExpression [18-22]
+            Identifier(T2) [18-20]
+            Identifier(b) [21-22]
+          Alias [23-27]
+            Identifier(b) [26-27]
+      FromClause [28-78]
+        Join(LAST) [46-78]
+          TablePathExpression [33-45]
+            PathExpression [33-39]
+              Identifier(Table1) [33-39]
+            Alias [40-45]
+              Identifier(T1) [43-45]
+          TablePathExpression [56-65]
+            PathExpression [56-62]
+              Identifier(Table2) [56-62]
+            Alias [63-65]
+              Identifier(T2) [63-65]
+          UsingClause [66-78]
+            Identifier(c) [73-74]
+            Identifier(d) [76-77]
+--
+SELECT
+  T1.a AS a,
+  T2.b AS b
+FROM
+  Table1 AS T1
+  LAST JOIN
+  Table2 AS T2
+  USING(c, d)
+==
+
 select a as x, b as y from Table1 as T1 inner join
     Table2 T2 on T2.x = T3.y join Table3 as T3 using(c);
 --
@@ -774,7 +818,7 @@ select * from A, B JOIN (C, D)
 ==
 
 # RIGHT JOIN and FULL JOIN require parentheses when following a comma join.
-select * FROM A, B {{INNER|CROSS|LEFT|RIGHT|FULL}} JOIN C
+select * FROM A, B {{INNER|CROSS|LEFT|LAST|RIGHT|FULL}} JOIN C
 --
 ALTERNATION GROUP: INNER
 --
@@ -863,6 +907,35 @@ FROM
   LEFT JOIN
   C
 --
+ALTERNATION GROUP: LAST
+--
+QueryStatement [0-30]
+  Query [0-30]
+    Select [0-30]
+      SelectList [7-8]
+        SelectColumn [7-8]
+          Star(*) [7-8]
+      FromClause [9-30]
+        Join(LAST) [19-30]
+          Join(COMMA) [15-18]
+            TablePathExpression [14-15]
+              PathExpression [14-15]
+                Identifier(A) [14-15]
+            TablePathExpression [17-18]
+              PathExpression [17-18]
+                Identifier(B) [17-18]
+          TablePathExpression [29-30]
+            PathExpression [29-30]
+              Identifier(C) [29-30]
+--
+SELECT
+  *
+FROM
+  A,
+  B
+  LAST JOIN
+  C
+--
 ALTERNATION GROUP: RIGHT
 --
 ERROR: Syntax error: RIGHT JOIN must be parenthesized when following a comma join.  Also, if the preceding comma join is a correlated CROSS JOIN that unnests an array, then CROSS JOIN syntax must be used in place of the comma join [at 1:20]
@@ -949,6 +1022,14 @@ select * FROM A, B, C, D JOIN E LEFT JOIN F RIGHT JOIN G
                                             ^
 ==
 
+# Comma join error happens even after chains of other joins.
+select * FROM A, B, C, D JOIN E LAST JOIN F RIGHT JOIN G
+--
+ERROR: Syntax error: RIGHT JOIN must be parenthesized when following a comma join.  Also, if the preceding comma join is a correlated CROSS JOIN that unnests an array, then CROSS JOIN syntax must be used in place of the comma join [at 1:45]
+select * FROM A, B, C, D JOIN E LAST JOIN F RIGHT JOIN G
+                                            ^
+==
+
 # Commas to the right of FULL/RIGHT join are okay.
 select * FROM A RIGHT JOIN B FULL JOIN C, D LEFT JOIN E
 --
diff --git a/zetasql/parser/testdata/orderby.test b/zetasql/parser/testdata/orderby.test
index 261d68fa8..a34225e81 100644
--- a/zetasql/parser/testdata/orderby.test
+++ b/zetasql/parser/testdata/orderby.test
@@ -591,10 +591,10 @@ FROM
 ORDER BY a DESC NULLS LAST
 ==
 
-select a from T order by 1 nulls last, first desc nulls first, last asc nulls last;
+select a from T order by 1 nulls last, first desc nulls first, `last` asc nulls last;
 --
-QueryStatement [0-82]
-  Query [0-82]
+QueryStatement [0-84]
+  Query [0-84]
     Select [0-15]
       SelectList [7-8]
         SelectColumn [7-8]
@@ -604,7 +604,7 @@ QueryStatement [0-82]
         TablePathExpression [14-15]
           PathExpression [14-15]
             Identifier(T) [14-15]
-    OrderBy [16-82]
+    OrderBy [16-84]
       OrderingExpression(ASC) [25-37]
         IntLiteral(1) [25-26]
         NullOrder(NULLS LAST) [27-37]
@@ -612,13 +612,13 @@ QueryStatement [0-82]
         PathExpression [39-44]
           Identifier(first) [39-44]
         NullOrder(NULLS FIRST) [50-61]
-      OrderingExpression(ASC EXPLICITLY) [63-82]
-        PathExpression [63-67]
-          Identifier(last) [63-67]
-        NullOrder(NULLS LAST) [72-82]
+      OrderingExpression(ASC EXPLICITLY) [63-84]
+        PathExpression [63-69]
+          Identifier(`last`) [63-69]
+        NullOrder(NULLS LAST) [74-84]
 --
 SELECT
   a
 FROM
   T
-ORDER BY 1 NULLS LAST, first DESC NULLS FIRST, last ASC NULLS LAST
+ORDER BY 1 NULLS LAST, first DESC NULLS FIRST, `last` ASC NULLS LAST

From 761419f862d559227d8b150a55ee72bcd5a48732 Mon Sep 17 00:00:00 2001
From: Chen22 <jingchen2222@gmail.com>
Date: Thu, 13 May 2021 18:24:42 -0700
Subject: [PATCH 2/3] feat: support last join order by 1. join and from clause
 support last join order by 2. add test case

---
 zetasql/parser/bison_parser.y      |  38 +++++-
 zetasql/parser/join_proccessor.cc  |   7 +-
 zetasql/parser/join_proccessor.h   |   1 +
 zetasql/parser/parse_tree_manual.h |  12 +-
 zetasql/parser/testdata/from.test  | 191 +++++++++++++++++++++++------
 5 files changed, 202 insertions(+), 47 deletions(-)

diff --git a/zetasql/parser/bison_parser.y b/zetasql/parser/bison_parser.y
index 3c0b112f5..84203b1e6 100644
--- a/zetasql/parser/bison_parser.y
+++ b/zetasql/parser/bison_parser.y
@@ -4631,7 +4631,6 @@ join_type:
     | "INNER" { $$ = zetasql::ASTJoin::INNER; }
     | "LEFT" opt_outer { $$ = zetasql::ASTJoin::LEFT; }
     | "RIGHT" opt_outer { $$ = zetasql::ASTJoin::RIGHT; }
-    | "LAST" { $$ = zetasql::ASTJoin::LAST; }
     | /* Nothing */  { $$ = zetasql::ASTJoin::DEFAULT_JOIN_TYPE; }
     ;
 
@@ -4658,7 +4657,20 @@ join:
         zetasql::parser::ErrorInfo error_info;
         auto node = zetasql::parser::JoinRuleAction(
             FirstNonEmptyLocation({@2, @3, @4, @5}), @$,
-            $1, $2, $3, $4, $6, $7, $8, parser, &error_info);
+            $1, $2, $3, $4, $6, $7, nullptr, $8, parser, &error_info);
+        if (node == nullptr) {
+          YYERROR_AND_ABORT_AT(error_info.location, error_info.message);
+        }
+
+        $$ = node;
+      }
+    | join_input opt_natural "LAST" join_hint "JOIN" opt_hint table_primary
+    opt_order_by_clause opt_on_or_using_clause_list
+      {
+        zetasql::parser::ErrorInfo error_info;
+        auto node = zetasql::parser::JoinRuleAction(
+            FirstNonEmptyLocation({@2, @3, @4, @5}), @$,
+            $1, $2, zetasql::ASTJoin::LAST, $4, $6, $7, $8, $9, parser, &error_info);
         if (node == nullptr) {
           YYERROR_AND_ABORT_AT(error_info.location, error_info.message);
         }
@@ -4716,7 +4728,7 @@ from_clause_contents:
         zetasql::parser::ErrorInfo error_info;
         auto node = zetasql::parser::JoinRuleAction(
             FirstNonEmptyLocation({@2, @3, @4, @5}), @$,
-            $1, $2, $3, $4, $6, $7, $8,
+            $1, $2, $3, $4, $6, $7, nullptr, $8,
             parser, &error_info);
         if (node == nullptr) {
           YYERROR_AND_ABORT_AT(error_info.location, error_info.message);
@@ -4724,7 +4736,25 @@ from_clause_contents:
 
         $$ = node;
       }
-    | "@"
+    | from_clause_contents opt_natural "LAST" join_hint "JOIN" opt_hint
+      table_primary opt_order_by_clause on_or_using_clause_list
+      {
+        // Give an error if we have a RIGHT or FULL JOIN following a comma
+        // join since our left-to-right binding would violate the standard.
+        // See (broken link).
+        zetasql::parser::ErrorInfo error_info;
+        auto node = zetasql::parser::JoinRuleAction(
+            FirstNonEmptyLocation({@2, @3, @4, @5}), @$,
+            $1, $2, zetasql::ASTJoin::LAST, $4, $6, $7, $8, $9,
+            parser, &error_info);
+        if (node == nullptr) {
+          YYERROR_AND_ABORT_AT(error_info.location, error_info.message);
+        }
+
+        $$ = node;
+      }
+    |
+    "@"
       {
         YYERROR_AND_ABORT_AT(
             @1, "Query parameters cannot be used in place of table names");
diff --git a/zetasql/parser/join_proccessor.cc b/zetasql/parser/join_proccessor.cc
index 647372027..5c9b82d38 100644
--- a/zetasql/parser/join_proccessor.cc
+++ b/zetasql/parser/join_proccessor.cc
@@ -400,7 +400,8 @@ ASTNode* JoinRuleAction(
     const zetasql_bison_parser::location& start_location,
     const zetasql_bison_parser::location& end_location, ASTNode* lhs,
     bool natural, ASTJoin::JoinType join_type, ASTJoin::JoinHint join_hint,
-    ASTNode* hint, ASTNode* table_primary, ASTNode* on_or_using_clause_list,
+    ASTNode* hint, ASTNode* table_primary, ASTNode* order_by,
+    ASTNode* on_or_using_clause_list,
     BisonParser* parser,
     ErrorInfo* error_info) {
   auto clause_list =
@@ -440,11 +441,11 @@ ASTNode* JoinRuleAction(
     }
     join = parser->CreateASTNode<ASTJoin>(
         start_location, end_location,
-        {lhs, hint, table_primary, on_or_using_clause});
+        {lhs, hint, table_primary, order_by, on_or_using_clause});
     join->set_transformation_needed(IsTransformationNeeded(lhs));
   } else {
     join = parser->CreateASTNode<ASTJoin>(
-        start_location, end_location, {lhs, hint, table_primary, clause_list});
+        start_location, end_location, {lhs, hint, table_primary, order_by, clause_list});
     join->set_transformation_needed(true);
   }
 
diff --git a/zetasql/parser/join_proccessor.h b/zetasql/parser/join_proccessor.h
index 43f407870..d7ec17327 100644
--- a/zetasql/parser/join_proccessor.h
+++ b/zetasql/parser/join_proccessor.h
@@ -394,6 +394,7 @@ ASTNode* JoinRuleAction(
     const zetasql_bison_parser::location& end_location, ASTNode* lhs,
     bool opt_natural, ASTJoin::JoinType join_type, ASTJoin::JoinHint join_hint,
     ASTNode* opt_hint, ASTNode* table_primary,
+    ASTNode* opt_order_by,
     ASTNode* opt_on_or_using_clause_list,
     BisonParser* parser, ErrorInfo* error_info);
 
diff --git a/zetasql/parser/parse_tree_manual.h b/zetasql/parser/parse_tree_manual.h
index 177644486..4664aa4b1 100644
--- a/zetasql/parser/parse_tree_manual.h
+++ b/zetasql/parser/parse_tree_manual.h
@@ -1302,6 +1302,8 @@ class ASTJoin final : public ASTTableExpression {
   const ASTHint* hint() const { return hint_; }
   const ASTTableExpression* lhs() const { return lhs_; }
   const ASTTableExpression* rhs() const { return rhs_; }
+  // If present, order rhs before apply using clause
+  const ASTOrderBy* order_by() const { return order_by_; }
   const ASTOnClause* on_clause() const { return on_clause_; }
   const ASTUsingClause* using_clause() const { return using_clause_; }
 
@@ -1331,6 +1333,7 @@ class ASTJoin final : public ASTTableExpression {
     fl.AddRequired(&lhs_);
     fl.AddOptional(&hint_, AST_HINT);
     fl.AddRequired(&rhs_);
+    fl.AddOptional(&order_by_, AST_ORDER_BY);
     fl.AddOptional(&on_clause_, AST_ON_CLAUSE);
     fl.AddOptional(&using_clause_, AST_USING_CLAUSE);
 
@@ -1345,6 +1348,7 @@ class ASTJoin final : public ASTTableExpression {
   const ASTHint* hint_ = nullptr;
   const ASTTableExpression* lhs_ = nullptr;
   const ASTTableExpression* rhs_ = nullptr;
+  const ASTOrderBy* order_by_ = nullptr;
   const ASTOnClause* on_clause_ = nullptr;
   const ASTUsingClause* using_clause_ = nullptr;
   const ASTOnOrUsingClauseList* clause_list_ = nullptr;
@@ -1405,10 +1409,10 @@ class ASTOnClause final : public ASTNode {
     FieldLoader fl(this);
     fl.AddRequired(&expression_);
   }
-
   const ASTExpression* expression_ = nullptr;
 };
 
+
 class ASTUsingClause final : public ASTNode {
  public:
   static constexpr ASTNodeKind kConcreteNodeKind = AST_USING_CLAUSE;
@@ -1418,6 +1422,9 @@ class ASTUsingClause final : public ASTNode {
   zetasql_base::StatusOr<VisitResult> Accept(
       NonRecursiveParseTreeVisitor* visitor) const override;
 
+  // If present, order dataset before apply using clause
+  const ASTOrderBy* order_by() const { return order_by_; }
+  
   const absl::Span<const ASTIdentifier* const>& keys() const {
     return keys_;
   }
@@ -1425,9 +1432,10 @@ class ASTUsingClause final : public ASTNode {
  private:
   void InitFields() final {
     FieldLoader fl(this);
+    fl.AddRequired(&order_by_);
     fl.AddRestAsRepeated(&keys_);
   }
-
+  const ASTOrderBy* order_by_ = nullptr;
   absl::Span<const ASTIdentifier* const> keys_;
 };
 
diff --git a/zetasql/parser/testdata/from.test b/zetasql/parser/testdata/from.test
index 6038f20ec..f673a20a1 100644
--- a/zetasql/parser/testdata/from.test
+++ b/zetasql/parser/testdata/from.test
@@ -134,6 +134,158 @@ FROM
   USING(c, d)
 ==
 
+select T1.a as a, T2.b as b from Table1 as T1 last join Table2 T2 order by e using (c, d);
+--
+QueryStatement [0-89]
+  Query [0-89]
+    Select [0-89]
+      SelectList [7-27]
+        SelectColumn [7-16]
+          PathExpression [7-11]
+            Identifier(T1) [7-9]
+            Identifier(a) [10-11]
+          Alias [12-16]
+            Identifier(a) [15-16]
+        SelectColumn [18-27]
+          PathExpression [18-22]
+            Identifier(T2) [18-20]
+            Identifier(b) [21-22]
+          Alias [23-27]
+            Identifier(b) [26-27]
+      FromClause [28-89]
+        Join(LAST) [46-89]
+          TablePathExpression [33-45]
+            PathExpression [33-39]
+              Identifier(Table1) [33-39]
+            Alias [40-45]
+              Identifier(T1) [43-45]
+          TablePathExpression [56-65]
+            PathExpression [56-62]
+              Identifier(Table2) [56-62]
+            Alias [63-65]
+              Identifier(T2) [63-65]
+          OrderBy [66-76]
+            OrderingExpression(ASC) [75-76]
+              PathExpression [75-76]
+                Identifier(e) [75-76]
+          UsingClause [77-89]
+            Identifier(c) [84-85]
+            Identifier(d) [87-88]
+--
+SELECT
+  T1.a AS a,
+  T2.b AS b
+FROM
+  Table1 AS T1
+  LAST JOIN
+  Table2 AS T2
+  ORDER BY e
+  USING(c, d)
+==
+
+select T1.a as a, T2.b as b from Table1 as T1 last join Table2 T2 on T1.c = T2.c;
+--
+QueryStatement [0-80]
+  Query [0-80]
+    Select [0-80]
+      SelectList [7-27]
+        SelectColumn [7-16]
+          PathExpression [7-11]
+            Identifier(T1) [7-9]
+            Identifier(a) [10-11]
+          Alias [12-16]
+            Identifier(a) [15-16]
+        SelectColumn [18-27]
+          PathExpression [18-22]
+            Identifier(T2) [18-20]
+            Identifier(b) [21-22]
+          Alias [23-27]
+            Identifier(b) [26-27]
+      FromClause [28-80]
+        Join(LAST) [46-80]
+          TablePathExpression [33-45]
+            PathExpression [33-39]
+              Identifier(Table1) [33-39]
+            Alias [40-45]
+              Identifier(T1) [43-45]
+          TablePathExpression [56-65]
+            PathExpression [56-62]
+              Identifier(Table2) [56-62]
+            Alias [63-65]
+              Identifier(T2) [63-65]
+          OnClause [66-80]
+            BinaryExpression(=) [69-80]
+              PathExpression [69-73]
+                Identifier(T1) [69-71]
+                Identifier(c) [72-73]
+              PathExpression [76-80]
+                Identifier(T2) [76-78]
+                Identifier(c) [79-80]
+--
+SELECT
+  T1.a AS a,
+  T2.b AS b
+FROM
+  Table1 AS T1
+  LAST JOIN
+  Table2 AS T2
+  ON T1.c = T2.c
+==
+
+select T1.a as a, T2.b as b from Table1 as T1 last join Table2 T2 order by e on T1.c = T2.c;
+--
+QueryStatement [0-91]
+  Query [0-91]
+    Select [0-91]
+      SelectList [7-27]
+        SelectColumn [7-16]
+          PathExpression [7-11]
+            Identifier(T1) [7-9]
+            Identifier(a) [10-11]
+          Alias [12-16]
+            Identifier(a) [15-16]
+        SelectColumn [18-27]
+          PathExpression [18-22]
+            Identifier(T2) [18-20]
+            Identifier(b) [21-22]
+          Alias [23-27]
+            Identifier(b) [26-27]
+      FromClause [28-91]
+        Join(LAST) [46-91]
+          TablePathExpression [33-45]
+            PathExpression [33-39]
+              Identifier(Table1) [33-39]
+            Alias [40-45]
+              Identifier(T1) [43-45]
+          TablePathExpression [56-65]
+            PathExpression [56-62]
+              Identifier(Table2) [56-62]
+            Alias [63-65]
+              Identifier(T2) [63-65]
+          OrderBy [66-76]
+            OrderingExpression(ASC) [75-76]
+              PathExpression [75-76]
+                Identifier(e) [75-76]
+          OnClause [77-91]
+            BinaryExpression(=) [80-91]
+              PathExpression [80-84]
+                Identifier(T1) [80-82]
+                Identifier(c) [83-84]
+              PathExpression [87-91]
+                Identifier(T2) [87-89]
+                Identifier(c) [90-91]
+--
+SELECT
+  T1.a AS a,
+  T2.b AS b
+FROM
+  Table1 AS T1
+  LAST JOIN
+  Table2 AS T2
+  ORDER BY e
+  ON T1.c = T2.c
+==
+
 select a as x, b as y from Table1 as T1 inner join
     Table2 T2 on T2.x = T3.y join Table3 as T3 using(c);
 --
@@ -818,7 +970,7 @@ select * from A, B JOIN (C, D)
 ==
 
 # RIGHT JOIN and FULL JOIN require parentheses when following a comma join.
-select * FROM A, B {{INNER|CROSS|LEFT|LAST|RIGHT|FULL}} JOIN C
+select * FROM A, B {{INNER|CROSS|LEFT|RIGHT|FULL}} JOIN C
 --
 ALTERNATION GROUP: INNER
 --
@@ -907,35 +1059,6 @@ FROM
   LEFT JOIN
   C
 --
-ALTERNATION GROUP: LAST
---
-QueryStatement [0-30]
-  Query [0-30]
-    Select [0-30]
-      SelectList [7-8]
-        SelectColumn [7-8]
-          Star(*) [7-8]
-      FromClause [9-30]
-        Join(LAST) [19-30]
-          Join(COMMA) [15-18]
-            TablePathExpression [14-15]
-              PathExpression [14-15]
-                Identifier(A) [14-15]
-            TablePathExpression [17-18]
-              PathExpression [17-18]
-                Identifier(B) [17-18]
-          TablePathExpression [29-30]
-            PathExpression [29-30]
-              Identifier(C) [29-30]
---
-SELECT
-  *
-FROM
-  A,
-  B
-  LAST JOIN
-  C
---
 ALTERNATION GROUP: RIGHT
 --
 ERROR: Syntax error: RIGHT JOIN must be parenthesized when following a comma join.  Also, if the preceding comma join is a correlated CROSS JOIN that unnests an array, then CROSS JOIN syntax must be used in place of the comma join [at 1:20]
@@ -1022,14 +1145,6 @@ select * FROM A, B, C, D JOIN E LEFT JOIN F RIGHT JOIN G
                                             ^
 ==
 
-# Comma join error happens even after chains of other joins.
-select * FROM A, B, C, D JOIN E LAST JOIN F RIGHT JOIN G
---
-ERROR: Syntax error: RIGHT JOIN must be parenthesized when following a comma join.  Also, if the preceding comma join is a correlated CROSS JOIN that unnests an array, then CROSS JOIN syntax must be used in place of the comma join [at 1:45]
-select * FROM A, B, C, D JOIN E LAST JOIN F RIGHT JOIN G
-                                            ^
-==
-
 # Commas to the right of FULL/RIGHT join are okay.
 select * FROM A RIGHT JOIN B FULL JOIN C, D LEFT JOIN E
 --

From e94b6db3abad9de8ff1f7928ddfdd02e0b0a3d4c Mon Sep 17 00:00:00 2001
From: Chen22 <jingchen2222@gmail.com>
Date: Thu, 13 May 2021 19:46:45 -0700
Subject: [PATCH 3/3] feat: add error syntax test case for last join without
 on/using clause

---
 zetasql/parser/testdata/from.test | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/zetasql/parser/testdata/from.test b/zetasql/parser/testdata/from.test
index f673a20a1..beb9185f3 100644
--- a/zetasql/parser/testdata/from.test
+++ b/zetasql/parser/testdata/from.test
@@ -970,7 +970,8 @@ select * from A, B JOIN (C, D)
 ==
 
 # RIGHT JOIN and FULL JOIN require parentheses when following a comma join.
-select * FROM A, B {{INNER|CROSS|LEFT|RIGHT|FULL}} JOIN C
+# LAST JOIN require to be followed by ON/USING clause
+select * FROM A, B {{INNER|CROSS|LEFT|RIGHT|FULL|LAST}} JOIN C
 --
 ALTERNATION GROUP: INNER
 --
@@ -1070,6 +1071,13 @@ ALTERNATION GROUP: FULL
 ERROR: Syntax error: FULL JOIN must be parenthesized when following a comma join.  Also, if the preceding comma join is a correlated CROSS JOIN that unnests an array, then CROSS JOIN syntax must be used in place of the comma join [at 1:20]
 select * FROM A, B FULL JOIN C
                    ^
+
+--
+ALTERNATION GROUP: LAST
+--
+ERROR: Syntax error: Expected keyword ON or keyword USING but got end of statement [at 1:31]
+select * FROM A, B LAST JOIN C
+                              ^
 ==
 
 # Comma join error happens even after chains of other joins.