fixed bug #910 (right type of ifnull function)

mysql-test/r/create.result:
  added test for bug #910 (right type of ifnull function)
mysql-test/t/create.test:
  added test for bug #910 (right type of ifnull function)
sql/field.h:
  added new constructors of Field_decimal, Field_tiny, Field_short, Field_float,
  Field_null, Field_year
  for using in Item::tmp_table_field_from_field_type
sql/item.cc:
  added Item::tmp_table_field_from_field_type
sql/item.h:
  added Item::tmp_table_field_from_field_type

mysql-test/r/create.result

@@ -310,3 +310,52 @@ t1	CREATE TABLE `t1` (
 ) TYPE=MyISAM CHARSET=latin1
 SET SESSION table_type=default;
 drop table t1;
+create table t1(a int,b int,c int unsigned,d date,e char,f datetime,g time,h blob);
+insert into t1(a)values(1);
+insert into t1(a,b,c,d,e,f,g,h)
+values(2,-2,2,'1825-12-14','a','2003-1-1 3:2:1','4:3:2','binary data');
+select * from t1;
+a	b	c	d	e	f	g	h
+1	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+2	-2	2	1825-12-14	a	2003-01-01 03:02:01	04:03:02	binary data
+select a, 
+ifnull(b,cast(-7 as signed)) as b, 
+ifnull(c,cast(7 as unsigned)) as c, 
+ifnull(d,cast('2000-01-01' as date)) as d, 
+ifnull(e,cast('b' as char)) as e,
+ifnull(f,cast('2000-01-01' as datetime)) as f, 
+ifnull(g,cast('5:4:3' as time)) as g,
+ifnull(h,cast('yet another binary data' as binary)) as h,
+addtime(cast('1:0:0' as time),cast('1:0:0' as time)) as dd 
+from t1;
+a	b	c	d	e	f	g	h	dd
+1	-7	7	2000-01-01	b	2000-01-01 00:00:00	05:04:03	yet another binary data	02:00:00
+2	-2	2	1825-12-14	a	2003-01-01 03:02:01	04:03:02	binary data	02:00:00
+create table t2
+select
+a, 
+ifnull(b,cast(-7                        as signed))   as b,
+ifnull(c,cast(7                         as unsigned)) as c,
+ifnull(d,cast('2000-01-01'              as date))     as d,
+ifnull(e,cast('b'                       as char))     as e,
+ifnull(f,cast('2000-01-01'              as datetime)) as f,
+ifnull(g,cast('5:4:3'                   as time))     as g,
+ifnull(h,cast('yet another binary data' as binary))   as h,
+addtime(cast('1:0:0' as time),cast('1:0:0' as time))  as dd
+from t1;
+explain t2;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	YES		NULL	
+b	bigint(11)			0	
+c	bigint(10)			0	
+d	date			0000-00-00	
+e	char(1)				
+f	datetime			0000-00-00 00:00:00	
+g	time			00:00:00	
+h	mediumblob				
+dd	time			00:00:00	
+select * from t2;
+a	b	c	d	e	f	g	h	dd
+1	-7	7	2000-01-01	b	2000-01-01 00:00:00	05:04:03	yet another binary data	02:00:00
+2	-2	2	1825-12-14	a	2003-01-01 03:02:01	04:03:02	binary data	02:00:00
+drop table t1, t2;

mysql-test/t/create.test

@@ -215,3 +215,41 @@ CREATE TABLE t1 (a int not null);
 show create table t1;
 SET SESSION table_type=default;
 drop table t1;
+
+#
+# Test types of data for create select with functions
+#
+
+create table t1(a int,b int,c int unsigned,d date,e char,f datetime,g time,h blob);
+insert into t1(a)values(1);
+insert into t1(a,b,c,d,e,f,g,h)
+values(2,-2,2,'1825-12-14','a','2003-1-1 3:2:1','4:3:2','binary data');
+select * from t1;
+select a, 
+    ifnull(b,cast(-7 as signed)) as b, 
+    ifnull(c,cast(7 as unsigned)) as c, 
+    ifnull(d,cast('2000-01-01' as date)) as d, 
+    ifnull(e,cast('b' as char)) as e,
+    ifnull(f,cast('2000-01-01' as datetime)) as f, 
+    ifnull(g,cast('5:4:3' as time)) as g,
+    ifnull(h,cast('yet another binary data' as binary)) as h,
+    addtime(cast('1:0:0' as time),cast('1:0:0' as time)) as dd 
+from t1;
+
+create table t2
+select
+    a, 
+    ifnull(b,cast(-7                        as signed))   as b,
+    ifnull(c,cast(7                         as unsigned)) as c,
+    ifnull(d,cast('2000-01-01'              as date))     as d,
+    ifnull(e,cast('b'                       as char))     as e,
+    ifnull(f,cast('2000-01-01'              as datetime)) as f,
+    ifnull(g,cast('5:4:3'                   as time))     as g,
+    ifnull(h,cast('yet another binary data' as binary))   as h,
+    addtime(cast('1:0:0' as time),cast('1:0:0' as time))  as dd
+from t1;
+explain t2;
+			
+select * from t2;
+
+drop table t1, t2;

sql/field.h

@@ -305,6 +305,11 @@ class Field_decimal :public Field_num {
 	       unireg_check_arg, field_name_arg, table_arg,
 	       dec_arg, zero_arg,unsigned_arg)
     {}
+  Field_decimal(uint32 len_arg,bool maybe_null_arg, const char *field_name_arg,
+		struct st_table *table_arg,bool unsigned_arg)
+    :Field_num((char*) 0, len_arg, maybe_null_arg ? (uchar*) "": 0,0,
+	       NONE, field_name_arg, table_arg,0,0,unsigned_arg)
+    {}
   enum_field_types type() const { return FIELD_TYPE_DECIMAL;}
   enum ha_base_keytype key_type() const
   { return zerofill ? HA_KEYTYPE_BINARY : HA_KEYTYPE_NUM; }
@@ -334,6 +339,11 @@ class Field_tiny :public Field_num {
 	       unireg_check_arg, field_name_arg, table_arg,
 	       0, zero_arg,unsigned_arg)
     {}
+  Field_tiny(uint32 len_arg,bool maybe_null_arg, const char *field_name_arg,
+	     struct st_table *table_arg,bool unsigned_arg)
+    :Field_num((char*) 0, len_arg, maybe_null_arg ? (uchar*) "": 0,0,
+	       NONE, field_name_arg, table_arg,0,0,unsigned_arg)
+    {}
   enum Item_result result_type () const { return INT_RESULT; }
   enum_field_types type() const { return FIELD_TYPE_TINY;}
   enum ha_base_keytype key_type() const
@@ -364,6 +374,11 @@ class Field_short :public Field_num {
 	       unireg_check_arg, field_name_arg, table_arg,
 	       0, zero_arg,unsigned_arg)
     {}
+  Field_short(uint32 len_arg,bool maybe_null_arg, const char *field_name_arg,
+	      struct st_table *table_arg,bool unsigned_arg)
+    :Field_num((char*) 0, len_arg, maybe_null_arg ? (uchar*) "": 0,0,
+	       NONE, field_name_arg, table_arg,0,0,unsigned_arg)
+    {}
   enum Item_result result_type () const { return INT_RESULT; }
   enum_field_types type() const { return FIELD_TYPE_SHORT;}
   enum ha_base_keytype key_type() const
@@ -497,6 +512,11 @@ class Field_float :public Field_num {
 	       unireg_check_arg, field_name_arg, table_arg,
 	       dec_arg, zero_arg,unsigned_arg)
     {}
+  Field_float(uint32 len_arg, bool maybe_null_arg, const char *field_name_arg,
+	      struct st_table *table_arg, uint8 dec_arg)
+    :Field_num((char*) 0, len_arg, maybe_null_arg ? (uchar*) "": 0, (uint) 0,
+	       NONE, field_name_arg, table_arg,dec_arg,0,0)
+    {}
   enum_field_types type() const { return FIELD_TYPE_FLOAT;}
   enum ha_base_keytype key_type() const { return HA_KEYTYPE_FLOAT; }
   int  store(const char *to,uint length,CHARSET_INFO *charset);
@@ -558,6 +578,11 @@ class Field_null :public Field_str {
     :Field_str(ptr_arg, len_arg, null, 1,
 	       unireg_check_arg, field_name_arg, table_arg, cs)
     {}
+  Field_null(uint32 len_arg, const char *field_name_arg,
+	     struct st_table *table_arg, CHARSET_INFO *cs)
+    :Field_str((char*) 0, len_arg, null, 1,
+	       NONE, field_name_arg, table_arg, cs)
+    {}
   enum_field_types type() const { return FIELD_TYPE_NULL;}
   int  store(const char *to, uint length, CHARSET_INFO *cs) { null[0]=1; return 0; }
   int  store(double nr)   { null[0]=1; return 0; }
@@ -627,6 +652,10 @@ class Field_year :public Field_tiny {
     :Field_tiny(ptr_arg, len_arg, null_ptr_arg, null_bit_arg,
 		unireg_check_arg, field_name_arg, table_arg, 1, 1)
     {}
+  Field_year(uint32 len_arg,bool maybe_null_arg, const char *field_name_arg,
+	     struct st_table *table_arg)
+    :Field_tiny(len_arg,maybe_null_arg,field_name_arg,table_arg,1)
+    {}
   enum_field_types type() const { return FIELD_TYPE_YEAR;}
   int  store(const char *to,uint length,CHARSET_INFO *charset);
   int  store(double nr);

sql/item.cc

@@ -983,6 +983,73 @@ enum_field_types Item::field_type() const
 	  FIELD_TYPE_DOUBLE);
 }
 
+Field *Item::tmp_table_field_from_field_type(TABLE *table)
+{
+  switch (field_type()) 
+  {
+  case MYSQL_TYPE_DECIMAL:
+    return new Field_decimal(max_length, maybe_null, name, table,
+			     unsigned_flag);
+  case MYSQL_TYPE_TINY:
+    return new Field_tiny(max_length, maybe_null, name, table,
+			  unsigned_flag);
+  case MYSQL_TYPE_SHORT:
+    return new Field_short(max_length, maybe_null, name, table,
+			   unsigned_flag);
+  case MYSQL_TYPE_LONG:
+    return new Field_long(max_length, maybe_null, name, table,
+			  unsigned_flag);
+  case MYSQL_TYPE_FLOAT:
+    return new Field_float(max_length, maybe_null, name, table, decimals);
+  case MYSQL_TYPE_DOUBLE:
+    return new Field_double(max_length, maybe_null, name, table, decimals);
+  case MYSQL_TYPE_NULL:
+    return new Field_null(max_length, name, table, &my_charset_bin);
+#ifdef HAVE_LONG_LONG
+  case MYSQL_TYPE_LONGLONG:
+    return new Field_longlong(max_length, maybe_null, name, table,
+			      unsigned_flag);
+#endif
+  case MYSQL_TYPE_NEWDATE:
+  case MYSQL_TYPE_INT24:
+    return new Field_long(max_length, maybe_null, name, table,
+			  unsigned_flag);
+  case MYSQL_TYPE_DATE:
+    return new Field_date(maybe_null, name, table, &my_charset_bin);
+  case MYSQL_TYPE_TIME:
+    return new Field_time(maybe_null, name, table, &my_charset_bin);
+  case MYSQL_TYPE_TIMESTAMP:
+  case MYSQL_TYPE_DATETIME:
+    return new Field_datetime(maybe_null, name, table, &my_charset_bin);
+  case MYSQL_TYPE_YEAR:
+    return new Field_year(max_length, maybe_null, name, table);
+  case MYSQL_TYPE_ENUM:
+  case MYSQL_TYPE_SET:
+    return new Field_long(max_length, maybe_null, name, table,
+			  unsigned_flag);
+  case MYSQL_TYPE_TINY_BLOB:
+  case MYSQL_TYPE_MEDIUM_BLOB:
+  case MYSQL_TYPE_LONG_BLOB:
+  case MYSQL_TYPE_BLOB:
+  case MYSQL_TYPE_GEOMETRY:
+    return new Field_blob(max_length, maybe_null, name, table, collation.collation);
+  case MYSQL_TYPE_VAR_STRING:
+    if (max_length > 255)
+      return new Field_blob(max_length, maybe_null, name, table, collation.collation);
+    else
+      return new Field_varstring(max_length, maybe_null, name, table, collation.collation);
+  case MYSQL_TYPE_STRING:
+    if (max_length > 255)
+      return new Field_blob(max_length, maybe_null, name, table, collation.collation);
+    else
+      return new Field_string(max_length, maybe_null, name, table, collation.collation);
+  default:
+    // This case should never be choosen
+    DBUG_ASSERT(0);
+    return 0;
+  }
+}
+
 /* ARGSUSED */
 void Item_field::make_field(Send_field *tmp_field)
 {

sql/item.h

@@ -180,6 +180,8 @@ class Item {
   virtual bool null_inside() { return 0; }
   // used in row subselects to get value of elements
   virtual void bring_value() {}
+
+  Field *tmp_table_field_from_field_type(TABLE *table);
 };
 
 

sql/item_cmpfunc.cc

@@ -687,8 +687,21 @@ Item_func_ifnull::fix_length_and_dec()
     agg_arg_collations(collation, args, arg_count);
   else if (cached_result_type != REAL_RESULT)
     decimals= 0;
+  
+  cached_field_type= args[0]->field_type();
+  if (cached_field_type != args[1]->field_type())
+    cached_field_type= Item_func::field_type();
+}
+
+enum_field_types Item_func_ifnull::field_type() const 
+{
+  return cached_field_type;
 }
 
+Field *Item_func_ifnull::tmp_table_field(TABLE *table)
+{
+  return tmp_table_field_from_field_type(table);
+}
 
 double
 Item_func_ifnull::val()

sql/item_cmpfunc.h

@@ -281,6 +281,8 @@ class Item_func_interval :public Item_int_func
 class Item_func_ifnull :public Item_func
 {
   enum Item_result cached_result_type;
+  enum_field_types cached_field_type;
+  bool field_type_defined;
 public:
   Item_func_ifnull(Item *a,Item *b)
     :Item_func(a,b), cached_result_type(INT_RESULT)
@@ -289,8 +291,10 @@ class Item_func_ifnull :public Item_func
   longlong val_int();
   String *val_str(String *str);
   enum Item_result result_type () const { return cached_result_type; }
+  enum_field_types field_type() const;
   void fix_length_and_dec();
   const char *func_name() const { return "ifnull"; }
+  Field *tmp_table_field(TABLE *table);
 };