hang in dummy natural join (no common columns) Bug #4807

mysql-test/r/join.result

@@ -283,6 +283,12 @@ ID	Value1	Value2
 SELECT * FROM t1 NATURAL JOIN t2 WHERE (Value1 = 'A' AND Value2 <> 'B') AND 1;
 ID	Value1	Value2
 drop table t1,t2;
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (b int);
+CREATE TABLE t3 (c int);
+SELECT * FROM t1 NATURAL JOIN t2 NATURAL JOIN t3;
+a	b	c
+DROP TABLE t1, t2, t3;
 create table t1 (i int);
 create table t2 (i int);
 create table t3 (i int);

mysql-test/t/join.test

@@ -284,6 +284,16 @@ SELECT * FROM t1 NATURAL JOIN t2 WHERE 1 AND Value1 = 'A' AND Value2 <> 'B';
 SELECT * FROM t1 NATURAL JOIN t2 WHERE (Value1 = 'A' AND Value2 <> 'B') AND 1;
 drop table t1,t2;
 
+#
+# dummy natural join (no common columns) Bug #4807
+#
+
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (b int);
+CREATE TABLE t3 (c int);
+SELECT * FROM t1 NATURAL JOIN t2 NATURAL JOIN t3;
+DROP TABLE t1, t2, t3;
+
 #
 # Test combination of join methods
 #

sql/sql_base.cc

@@ -2522,6 +2522,8 @@ int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds)
       // to prevent natural join processing during PS re-execution
       table->natural_join= 0;
 
+      if (cond_and->list.elements)
+      {
         if (!table->outer_join)			// Not left join
         {
           *conds= and_conds(*conds, cond_and);
@@ -2548,6 +2550,7 @@ int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds)
         }
       }
     }
+  }
 
   if (stmt)
   {