Fixes for bugs #2508 and #2552

mysql-test/r/union.result:
  Test cases for bugs #2508 and #2552
mysql-test/t/union.test:
  Test cases for bugs #2508 and #2552
sql/sql_class.h:
  A fix for a bug #2508
sql/sql_select.cc:
  A fix for a bug #2508
sql/sql_union.cc:
  a fix for a bug #2552

mysql-test/r/union.result

@@ -539,7 +539,7 @@ aa
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` char(2) NOT NULL default ''
+  `a` char(2) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT 12 as a UNION select "aa" as a;
@@ -550,7 +550,7 @@ aa
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` char(2) NOT NULL default ''
+  `a` char(2) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT 12 as a UNION select 12.2 as a;
@@ -561,7 +561,7 @@ a
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` double(4,1) NOT NULL default '0.0'
+  `a` double(4,1) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t2 (it1 tinyint, it2 tinyint not null, i int not null, ib bigint, f float, d double, y year, da date, dt datetime, sc char(10), sv varchar(10), b blob, tx text);
@@ -585,7 +585,7 @@ it2
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `it2` int(11) NOT NULL default '0'
+  `it2` int(11) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT i from t2 UNION select f from t2;
@@ -799,7 +799,7 @@ select * from t1;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `1` bigint(1) NOT NULL default '0'
+  `1` bigint(1) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 select _latin1"test" union select _latin2"testt" ;
@@ -808,7 +808,7 @@ create table t1 select _latin2"test" union select _latin2"testt" ;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `test` char(5) character set latin2 NOT NULL default ''
+  `test` char(5) character set latin2 default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 (s char(200));
@@ -869,3 +869,27 @@ show status like 'Slow_queries';
 Variable_name	Value
 Slow_queries	3
 drop table t1;
+create table t1 (   RID int(11) not null default '0',   IID int(11) not null default '0',    nada varchar(50)  not null,NAME varchar(50) not null,PHONE varchar(50) not null) engine=MyISAM;
+insert into t1 ( RID,IID,nada,NAME,PHONE) values (1, 1, 'main', 'a', '111'), (2, 1, 'main', 'b', '222'), (3, 1, 'main', 'c', '333'), (4, 1, 'main', 'd', '444'), (5, 1, 'main', 'e', '555'), (6, 2, 'main', 'c', '333'), (7, 2, 'main', 'd', '454'), (8, 2, 'main', 'e', '555'), (9, 2, 'main', 'f', '666'), (10, 2, 'main', 'g', '777');
+select A.NAME, A.PHONE, B.NAME, B.PHONE from t1 A left join t1 B on A.NAME = B.NAME and B.IID = 2 where A.IID = 1 and (A.PHONE <> B.PHONE or B.NAME is null) union select A.NAME, A.PHONE, B.NAME, B.PHONE from t1 B left join t1 A on B.NAME = A.NAME and A.IID = 1 where B.IID = 2 and (A.PHONE <> B.PHONE or A.NAME is null);
+NAME	PHONE	NAME	PHONE
+a	111	NULL	NULL
+b	222	NULL	NULL
+d	444	d	454
+NULL	NULL	f	666
+NULL	NULL	g	777
+drop  table t1;
+create table t1 (  id int,  name char(10) not null,  name2 char(10) not null ) engine=innodb;
+insert into t1 values(1,'first','fff'),(2,'second','sss'),(3,'third','ttt');
+select name2 from t1  union all  select name from t1 union all select id from t1;
+name2
+fff
+sss
+ttt
+first
+second
+third
+1
+2
+3
+drop table t1;

mysql-test/t/union.test

@@ -465,3 +465,12 @@ show status like 'Slow_queries';
 select count(*) from t1 where a=7 union select count(*) from t1 where b=13;
 show status like 'Slow_queries';
 drop table t1;
+create table t1 (   RID int(11) not null default '0',   IID int(11) not null default '0',    nada varchar(50)  not null,NAME varchar(50) not null,PHONE varchar(50) not null) engine=MyISAM;
+insert into t1 ( RID,IID,nada,NAME,PHONE) values (1, 1, 'main', 'a', '111'), (2, 1, 'main', 'b', '222'), (3, 1, 'main', 'c', '333'), (4, 1, 'main', 'd', '444'), (5, 1, 'main', 'e', '555'), (6, 2, 'main', 'c', '333'), (7, 2, 'main', 'd', '454'), (8, 2, 'main', 'e', '555'), (9, 2, 'main', 'f', '666'), (10, 2, 'main', 'g', '777');
+select A.NAME, A.PHONE, B.NAME, B.PHONE from t1 A left join t1 B on A.NAME = B.NAME and B.IID = 2 where A.IID = 1 and (A.PHONE <> B.PHONE or B.NAME is null) union select A.NAME, A.PHONE, B.NAME, B.PHONE from t1 B left join t1 A on B.NAME = A.NAME and A.IID = 1 where B.IID = 2 and (A.PHONE <> B.PHONE or A.NAME is null);
+drop  table t1;
+create table t1 (  id int,  name char(10) not null,  name2 char(10) not null ) engine=innodb;
+insert into t1 values(1,'first','fff'),(2,'second','sss'),(3,'third','ttt');
+select name2 from t1  union all  select name from t1 union all select id from t1;
+drop table t1;
+

sql/sql_class.h

@@ -1075,11 +1075,11 @@ class TMP_TABLE_PARAM :public Sql_alloc
   uint  hidden_field_count;
   uint	group_parts,group_length,group_null_parts;
   uint	quick_group;
-  bool  using_indirect_summary_function;
+  bool  using_indirect_summary_function, all_nulls;
 
   TMP_TABLE_PARAM()
     :copy_funcs_it(copy_funcs), copy_field(0), group_parts(0),
-    group_length(0), group_null_parts(0)
+    group_length(0), group_null_parts(0), all_nulls(0)
   {}
   ~TMP_TABLE_PARAM()
   {

sql/sql_select.cc

@@ -4946,6 +4946,8 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 			     tmp_from_field, group != 0,not_all_columns);
 	  if (!new_field)
 	    goto err;					// Should be OOM
+	  if (param->all_nulls)
+	    new_field->flags&= ~NOT_NULL_FLAG;	// Because of outer join
 	  tmp_from_field++;
 	  *(reg_field++)= new_field;
 	  reclength+=new_field->pack_length();
@@ -4981,6 +4983,8 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 	  goto err;				// Got OOM
 	continue;				// Some kindf of const item
       }
+      if (param->all_nulls)
+	new_field->flags&= ~NOT_NULL_FLAG;	// Because of outer join
       if (type == Item::SUM_FUNC_ITEM)
 	((Item_sum *) item)->result_field= new_field;
       tmp_from_field++;

sql/sql_union.cc

@@ -206,6 +206,7 @@ int st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
   if (first_select->next_select())
   {
     union_result->tmp_table_param.field_count= types.elements;
+    union_result->tmp_table_param.all_nulls= true;
     if (!(table= create_tmp_table(thd_arg,
 				  &union_result->tmp_table_param, types,
 				  (ORDER*) 0, !union_option, 1, 
@@ -315,6 +316,7 @@ int st_select_lex_unit::exec()
 	  if it use same tables
 	*/
 	uint tablenr=0;
+	ulong query_id= thd->query_id;
 	for (TABLE_LIST *table_list= (TABLE_LIST*) sl->table_list.first;
 	     table_list;
 	     table_list= table_list->next, tablenr++)
@@ -329,6 +331,8 @@ int st_select_lex_unit::exec()
 	    */
 	    setup_table_map(table_list->table, table_list, tablenr);
 	  }
+	  for (unsigned int i=0; i < table_list->table->fields; i++)
+	    table_list->table->field[i]->query_id= query_id;
 	}
 	res= sl->join->optimize();
       }