From 3efd251ae3dac657b5576f111f70564ba3d7f289 Mon Sep 17 00:00:00 2001
From: unknown <timour@mysql.com>
Date: Tue, 25 Oct 2005 09:00:57 +0300
Subject: [PATCH] Fix for BUG#13832 - Unknown column t1.a in 'on clause'.

The cause for the bug is that the priorities of all rules/terminals
that process the FROM clause are not fully specified, and the
parser generator produces a parser that doesn't always parse
the FROM clause so that JOINs are left-associative. As a result
the final join tree produced by the parser is incorrect, which
is the cause for subsequent name resolution to fail.


mysql-test/r/select.result:
  Test for BUG#13832.
mysql-test/t/select.test:
  Test for BUG#13832.
sql/sql_yacc.yy:
  Fix for BUG#13832 - Unknown column t1.a in 'on clause'.

  List all join-related operators as having lower priority
  than the join operands to make the parser process join-
  related productions from left to right.
---
 mysql-test/r/select.result | 12 ++++++++++++
 mysql-test/t/select.test   | 14 ++++++++++++++
 sql/sql_yacc.yy            | 32 +++++++++++++++++++++++---------
 3 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/mysql-test/r/select.result b/mysql-test/r/select.result
index abf607dd438..57788800f60 100644
--- a/mysql-test/r/select.result
+++ b/mysql-test/r/select.result
@@ -3124,3 +3124,15 @@ from t1 inner join (t2 right join t3 on t2.id = t3.b_id) on t1.id = t3.a_id;
 count(*)
 6
 drop table t1,t2,t3;
+create table t1 (a int);
+create table t2 (b int);
+create table t3 (c int);
+select * from t1 join t2 join t3 on (t1.a=t3.c);
+a	b	c
+select * from t1 join t2 left join t3 on (t1.a=t3.c);
+a	b	c
+select * from t1 join t2 right join t3 on (t1.a=t3.c);
+a	b	c
+select * from t1 join t2 straight_join t3 on (t1.a=t3.c);
+a	b	c
+drop table t1, t2 ,t3;
diff --git a/mysql-test/t/select.test b/mysql-test/t/select.test
index 6fc149e2e1f..3044aa466a2 100644
--- a/mysql-test/t/select.test
+++ b/mysql-test/t/select.test
@@ -2649,3 +2649,17 @@ select count(*)
 from t1 inner join (t2 right join t3 on t2.id = t3.b_id) on t1.id = t3.a_id;
 
 drop table t1,t2,t3;
+
+#
+# Bug #13832 Incorrect parse order of join productions due to unspecified
+# operator priorities results in incorrect join tree.
+#
+
+create table t1 (a int);
+create table t2 (b int);
+create table t3 (c int);
+select * from t1 join t2 join t3 on (t1.a=t3.c);
+select * from t1 join t2 left join t3 on (t1.a=t3.c);
+select * from t1 join t2 right join t3 on (t1.a=t3.c);
+select * from t1 join t2 straight_join t3 on (t1.a=t3.c);
+drop table t1, t2 ,t3;
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 14f617b9f8b..f44120ae1a8 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -660,7 +660,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 %token  YEAR_SYM
 %token  ZEROFILL
 
-%left   JOIN_SYM
+%left   JOIN_SYM INNER_SYM STRAIGHT_JOIN CROSS LEFT RIGHT
 /* A dummy token to force the priority of table_ref production in a join. */
 %left   TABLE_REF_PRIORITY
 %left   SET_VAR
@@ -5225,14 +5225,22 @@ derived_table_list:
           }
         ;
 
+/*
+  Notice that JOIN is a left-associative operation, and it must be parsed
+  as such, that is, the parser must process first the left join operand
+  then the right one. Such order of processing ensures that the parser
+  produces correct join trees which is essential for semantic analysis
+  and subsequent optimization phases.
+*/
 join_table:
+/* INNER JOIN variants */
         /*
-          Evaluate production 'table_ref' before 'normal_join' so that
-          [INNER | CROSS] JOIN is properly nested as other left-associative
-          joins.
+          Use %prec to evaluate production 'table_ref' before 'normal_join'
+          so that [INNER | CROSS] JOIN is properly nested as other
+          left-associative joins.
         */
         table_ref %prec TABLE_REF_PRIORITY normal_join table_ref
-        { YYERROR_UNLESS($1 && ($$=$3)); }
+          { YYERROR_UNLESS($1 && ($$=$3)); }
 	| table_ref STRAIGHT_JOIN table_factor
 	  { YYERROR_UNLESS($1 && ($$=$3)); $3->straight=1; }
 	| table_ref normal_join table_ref
@@ -5274,6 +5282,13 @@ join_table:
 	  }
 	  '(' using_list ')'
           { add_join_natural($1,$3,$7); $$=$3; }
+	| table_ref NATURAL JOIN_SYM table_factor
+	  {
+            YYERROR_UNLESS($1 && ($$=$4));
+            add_join_natural($1,$4,NULL);
+          }
+
+/* LEFT JOIN variants */
 	| table_ref LEFT opt_outer JOIN_SYM table_ref
           ON
           {
@@ -5305,6 +5320,8 @@ join_table:
 	    $6->outer_join|=JOIN_TYPE_LEFT;
 	    $$=$6;
 	  }
+
+/* RIGHT JOIN variants */
 	| table_ref RIGHT opt_outer JOIN_SYM table_ref
           ON
           {
@@ -5342,10 +5359,7 @@ join_table:
 	    LEX *lex= Lex;
             if (!($$= lex->current_select->convert_right_join()))
               YYABORT;
-	  }
-	| table_ref NATURAL JOIN_SYM table_factor
-	  { YYERROR_UNLESS($1 && ($$=$4)); add_join_natural($1,$4,NULL); };
-
+	  };
 
 normal_join:
 	JOIN_SYM		{}