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

1 files changed, 29 insertions, 0 deletions

diff --git a/sql/field.h b/sql/field.h
index 79c45a99a43..a69178b4c92 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -305,6 +305,11 @@ public:
 	       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 @@ public:
 	       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 @@ public:
 	       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 @@ public:
 	       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 @@ public:
     :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 @@ public:
     :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);