From 20a2e1d0ac46e375ee7246576b541624c6f8f028 Mon Sep 17 00:00:00 2001
From: unknown <sanja@askmonty.org>
Date: Thu, 21 Jul 2011 11:20:55 +0300
Subject: [PATCH] Fix of LP BUG#777809

There are 2 volatile condition constructions AND/OR constructions and fields(references) when first
good supported to be top elements of conditions because it is normal practice
(see copy_andor_structure for example) fields without any expression in the condition is really rare
and mostly useless case however it could lead to problems when optimiser changes/moves them unaware
of other variables referring to them. An easy solution of this problem is just to replace single field
in a condition with equivalent expression well supported by the server (<field> -> <field> != 0).

mysql-test/r/view.result:
  New test added.
mysql-test/t/view.test:
  New test added.
sql/sql_parse.cc:
  <field> -> <field> != 0
sql/sql_yacc.yy:
  <field> -> <field> != 0
---
 mysql-test/r/view.result | 17 +++++++++++++++++
 mysql-test/t/view.test   | 20 ++++++++++++++++++++
 sql/sql_parse.cc         | 23 +++++++++++++++++++++++
 sql/sql_yacc.yy          |  6 +++---
 4 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/mysql-test/r/view.result b/mysql-test/r/view.result
index 80f19bd2fa9..93ebb3365b4 100644
--- a/mysql-test/r/view.result
+++ b/mysql-test/r/view.result
@@ -3906,6 +3906,23 @@ SELECT * FROM v1;
 a
 DROP VIEW v1;
 DROP TABLE t1;
+#
+# LP BUG#777809 (a retrograded condition for view ON)
+#
+CREATE TABLE t1 ( f1 int NOT NULL , f6 int NOT NULL ) ;
+INSERT IGNORE INTO t1 VALUES (20, 2);
+CREATE TABLE t2 ( f3 int NOT NULL ) ;
+INSERT IGNORE INTO t2 VALUES (7);
+CREATE OR REPLACE VIEW v2 AS SELECT * FROM t2;
+PREPARE prep_stmt FROM 'SELECT t1.f6 FROM t1 RIGHT JOIN v2 ON v2.f3 WHERE t1.f1 != 0';
+EXECUTE prep_stmt;
+f6
+2
+EXECUTE prep_stmt;
+f6
+2
+drop view v2;
+drop table t1,t2;
 # -----------------------------------------------------------------
 # -- End of 5.1 tests.
 # -----------------------------------------------------------------
diff --git a/mysql-test/t/view.test b/mysql-test/t/view.test
index 2eed4fad18d..644fbe0443f 100644
--- a/mysql-test/t/view.test
+++ b/mysql-test/t/view.test
@@ -3953,6 +3953,26 @@ SELECT * FROM v1;
 DROP VIEW v1;
 DROP TABLE t1;
 
+--echo #
+--echo # LP BUG#777809 (a retrograded condition for view ON)
+--echo #
+
+CREATE TABLE t1 ( f1 int NOT NULL , f6 int NOT NULL ) ;
+INSERT IGNORE INTO t1 VALUES (20, 2);
+
+CREATE TABLE t2 ( f3 int NOT NULL ) ;
+INSERT IGNORE INTO t2 VALUES (7);
+
+CREATE OR REPLACE VIEW v2 AS SELECT * FROM t2;
+
+PREPARE prep_stmt FROM 'SELECT t1.f6 FROM t1 RIGHT JOIN v2 ON v2.f3 WHERE t1.f1 != 0';
+
+EXECUTE prep_stmt;
+EXECUTE prep_stmt;
+
+drop view v2;
+drop table t1,t2;
+
 --echo # -----------------------------------------------------------------
 --echo # -- End of 5.1 tests.
 --echo # -----------------------------------------------------------------
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 1544c13f666..1d833d540a5 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -6890,6 +6890,28 @@ push_new_name_resolution_context(THD *thd,
 }
 
 
+/**
+  Fix condition which contains only field (f turns to  f <> 0 )
+
+  @param cond            The condition to fix
+
+  @return fixed condition
+*/
+
+Item *normalize_cond(Item *cond)
+{
+  if (cond)
+  {
+    Item::Type type= cond->type();
+    if (type == Item::FIELD_ITEM || type == Item::REF_ITEM)
+    {
+      cond= new Item_func_ne(cond, new Item_int(0));
+    }
+  }
+  return cond;
+}
+
+
 /**
   Add an ON condition to the second operand of a JOIN ... ON.
 
@@ -6908,6 +6930,7 @@ void add_join_on(TABLE_LIST *b, Item *expr)
 {
   if (expr)
   {
+    expr= normalize_cond(expr);
     if (!b->on_expr)
       b->on_expr= expr;
     else
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 6f89b2bd837..c84b549bbc0 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -9029,7 +9029,7 @@ where_clause:
           expr
           {
             SELECT_LEX *select= Select;
-            select->where= $3;
+            select->where= normalize_cond($3);
             select->parsing_place= NO_MATTER;
             if ($3)
               $3->top_level_item();
@@ -9045,7 +9045,7 @@ having_clause:
           expr
           {
             SELECT_LEX *sel= Select;
-            sel->having= $3;
+            sel->having= normalize_cond($3);
             sel->parsing_place= NO_MATTER;
             if ($3)
               $3->top_level_item();
@@ -10483,7 +10483,7 @@ wild_and_where:
           }
         | WHERE expr
           {
-            Select->where= $2;
+            Select->where= normalize_cond($2);
             if ($2)
               $2->top_level_item();
           }