BUG#14480, attempt2: In CREATE ... SELECT ..., don't count the same field twice

when calculating table->null_fields.


mysql-test/r/create.result:
  Testcase for BUG#14480
mysql-test/t/create.test:
  Testcase for BUG#14480
sql/sql_table.cc:
  BUG#14480: For CREATE ... SELECT ... a field list passed to mysql_prepare_table() contains
  instances of create_field for both create-list and select-list. mysql_prepare_table() 
  matches elements that refer to the same field, and joins them together. When the "join"  
  is performed, both of create_field structures has already been counted in "null_fields". 
  
  This fix makes sure that "null_fields" contains the correct value after two create_field 
  structures have been joined.

mysql-test/r/create.result

@@ -1,4 +1,4 @@
-drop table if exists t1,t2,t3;
+drop table if exists t1,t2,t3,t4,t5;
 drop database if exists mysqltest;
 create table t1 (b char(0));
 insert into t1 values (""),(null);
@@ -632,3 +632,69 @@ t1	CREATE TABLE `t1` (
   PRIMARY KEY  (`a`)
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
+CREATE TABLE t2 (
+a int(11) default NULL
+);
+insert into t2 values(111);
+create table t1 ( 
+a varchar(12) charset utf8 collate utf8_bin not null, 
+b int not null, primary key (a)
+) select a, 1 as b from t2 ;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` varchar(12) character set utf8 collate utf8_bin NOT NULL default '',
+  `b` int(11) NOT NULL default '0',
+  PRIMARY KEY  (`a`)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1;
+create table t1 ( 
+a varchar(12) charset utf8 collate utf8_bin not null,
+b int not null, primary key (a)
+) select 'a' as a , 1 as b from t2 ;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` varchar(12) character set utf8 collate utf8_bin NOT NULL default '',
+  `b` int(11) NOT NULL default '0',
+  PRIMARY KEY  (`a`)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1;
+create table t1 ( 
+a varchar(12) charset utf8 collate utf8_bin,
+b int not null, primary key (a)
+) select 'a' as a , 1 as b from t2 ;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` varchar(12) character set utf8 collate utf8_bin NOT NULL default '',
+  `b` int(11) NOT NULL default '0',
+  PRIMARY KEY  (`a`)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1, t2;
+create table t1 ( 
+a1 int not null,
+a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int
+);
+insert into t1 values (1,1,1, 1,1,1, 1,1,1);
+create table t2 ( 
+a1 varchar(12) charset utf8 collate utf8_bin not null,
+a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int,
+primary key (a1)
+) select a1,a2,a3,a4,a5,a6,a7,a8,a9 from t1 ;
+drop table t2;
+create table t2 ( 
+a1 varchar(12) charset utf8 collate utf8_bin,
+a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int
+) select a1,a2,a3,a4,a5,a6,a7,a8,a9 from t1;
+drop table t1, t2;
+create table t1 ( 
+a1 int, a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int
+);
+insert into t1 values (1,1,1, 1,1,1, 1,1,1);
+create table t2 ( 
+a1 varchar(12) charset utf8 collate utf8_bin not null,
+a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int,
+primary key (a1)
+) select a1,a2,a3,a4,a5,a6,a7,a8,a9 from t1 ;
+drop table t1, t2;

mysql-test/t/create.test

@@ -3,7 +3,7 @@
 #
 
 --disable_warnings
-drop table if exists t1,t2,t3;
+drop table if exists t1,t2,t3,t4,t5;
 drop database if exists mysqltest;
 --enable_warnings
 
@@ -534,4 +534,66 @@ create table t1 (
 show create table t1;
 drop table t1;
 
+#
+# BUG#14480: assert failure in CREATE ... SELECT because of wrong
+#            calculation of number of NULLs.
+#
+CREATE TABLE t2 (
+  a int(11) default NULL
+);
+insert into t2 values(111);
+
+create table t1 ( 
+  a varchar(12) charset utf8 collate utf8_bin not null, 
+  b int not null, primary key (a)
+) select a, 1 as b from t2 ;
+show create table t1;
+drop table t1;
+
+create table t1 ( 
+  a varchar(12) charset utf8 collate utf8_bin not null,
+  b int not null, primary key (a)
+) select 'a' as a , 1 as b from t2 ;
+show create table t1;
+drop table t1;
+
+create table t1 ( 
+  a varchar(12) charset utf8 collate utf8_bin,
+  b int not null, primary key (a)
+) select 'a' as a , 1 as b from t2 ;
+show create table t1;
+drop table t1, t2;
+
+create table t1 ( 
+  a1 int not null,
+  a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int
+);
+insert into t1 values (1,1,1, 1,1,1, 1,1,1);
+
+create table t2 ( 
+  a1 varchar(12) charset utf8 collate utf8_bin not null,
+  a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int,
+  primary key (a1)
+) select a1,a2,a3,a4,a5,a6,a7,a8,a9 from t1 ;
+drop table t2;
+
+create table t2 ( 
+  a1 varchar(12) charset utf8 collate utf8_bin,
+  a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int
+) select a1,a2,a3,a4,a5,a6,a7,a8,a9 from t1;
+
+drop table t1, t2;
+create table t1 ( 
+  a1 int, a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int
+);
+insert into t1 values (1,1,1, 1,1,1, 1,1,1);
+
+create table t2 ( 
+  a1 varchar(12) charset utf8 collate utf8_bin not null,
+  a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int,
+  primary key (a1)
+) select a1,a2,a3,a4,a5,a6,a7,a8,a9 from t1 ;
+
+drop table t1, t2;
+
 # End of 4.1 tests

sql/sql_table.cc

@@ -647,8 +647,15 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
           sql_field->pack_length=	dup_field->pack_length;
 	  sql_field->create_length_to_internal_length();
 	  sql_field->decimals=		dup_field->decimals;
-	  sql_field->flags=		dup_field->flags;
 	  sql_field->unireg_check=	dup_field->unireg_check;
+          /* 
+            We're making one field from two, the result field will have
+            dup_field->flags as flags. If we've incremented null_fields
+            because of sql_field->flags, decrement it back.
+          */
+          if (!(sql_field->flags & NOT_NULL_FLAG))
+            null_fields--;
+	  sql_field->flags=		dup_field->flags;
 	  it2.remove();			// Remove first (create) definition
 	  select_field_pos--;
 	  break;