fixed union types merging and table related metadata (BUG#8824)

mysql-test/r/func_group.result:
  new result
mysql-test/r/metadata.result:
  new result
  test of metadata of variables, unions and derived tables
mysql-test/r/union.result:
  new results
  test of union of enum
mysql-test/t/metadata.test:
  test of metadata of variables, unions and derived tables
mysql-test/t/union.test:
  test of union of enum
sql/field.cc:
  Field type merging rules added
  Fixed table name/alias returting for field made from temporary tables
sql/field.h:
  removed unned field type reporting
sql/item.cc:
  fixed bug in NEW_DATE type field creartion
  replaced mechanism of merging types of UNION
sql/item.h:
  replaced mechanism of merging types of UNION
sql/item_func.h:
  new item type to make correct field type detection possible
sql/item_subselect.cc:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_derived.cc:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_lex.h:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_parse.cc:
  made function for enum/set pack length calculation
sql/sql_prepare.cc:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_select.cc:
  new temporary table field creation by Item_type_holder
  fixed table alias for temporary table
sql/sql_union.cc:
  added table name parameter to prepare() to show right table alias for derived tables

1 files changed, 13 insertions, 35 deletions

diff --git a/sql/field.h b/sql/field.h
index b5d88504939..5dc124aba35 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -31,6 +31,17 @@ class Protocol;
 struct st_cache_field;
 void field_conv(Field *to,Field *from);
 
+inline uint get_enum_pack_length(int elements)
+{
+  return elements < 256 ? 1 : 2;
+}
+
+inline uint get_set_pack_length(int elements)
+{
+  uint len= (elements + 7) / 8;
+  return len > 4 ? 8 : len;
+}
+
 class Field
 {
   Field(const Item &);				/* Prevent use of these */
@@ -75,17 +86,6 @@ public:
     GEOM_GEOMETRYCOLLECTION = 7
   };
   enum imagetype { itRAW, itMBR};
-  enum field_cast_enum
-  {
-    FIELD_CAST_STOP, FIELD_CAST_DECIMAL, FIELD_CAST_TINY, FIELD_CAST_SHORT,
-    FIELD_CAST_MEDIUM, FIELD_CAST_LONG, FIELD_CAST_LONGLONG,
-    FIELD_CAST_FLOAT, FIELD_CAST_DOUBLE,
-    FIELD_CAST_NULL,
-    FIELD_CAST_TIMESTAMP, FIELD_CAST_YEAR, FIELD_CAST_DATE, FIELD_CAST_NEWDATE,
-    FIELD_CAST_TIME, FIELD_CAST_DATETIME,
-    FIELD_CAST_STRING, FIELD_CAST_VARSTRING, FIELD_CAST_BLOB,
-    FIELD_CAST_GEOM, FIELD_CAST_ENUM, FIELD_CAST_SET
-  };
 
   utype		unireg_check;
   uint32	field_length;		// Length of field
@@ -119,6 +119,8 @@ public:
   virtual String *val_str(String*,String *)=0;
   virtual Item_result result_type () const=0;
   virtual Item_result cmp_type () const { return result_type(); }
+  static enum_field_types field_type_merge(enum_field_types, enum_field_types);
+  static Item_result result_merge_type(enum_field_types);
   bool eq(Field *field) { return ptr == field->ptr && null_ptr == field->null_ptr; }
   virtual bool eq_def(Field *field);
   virtual uint32 pack_length() const { return (uint32) field_length; }
@@ -290,8 +292,6 @@ public:
                             int cuted_increment);
   void set_datetime_warning(const uint level, const uint code, 
                             double nr, timestamp_type ts_type);
-  virtual field_cast_enum field_cast_type()= 0;
-  bool field_cast_compatible(field_cast_enum type);
   /* maximum possible display length */
   virtual uint32 max_length()= 0;
   friend bool reopen_table(THD *,struct st_table *,bool);
@@ -398,7 +398,6 @@ public:
   bool zero_pack() const { return 0; }
   void sql_type(String &str) const;
   uint32 max_length() { return field_length; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_DECIMAL; }
 };
 
 
@@ -430,7 +429,6 @@ public:
   uint32 pack_length() const { return 1; }
   void sql_type(String &str) const;
   uint32 max_length() { return 4; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_TINY; }
 };
 
 
@@ -467,7 +465,6 @@ public:
   uint32 pack_length() const { return 2; }
   void sql_type(String &str) const;
   uint32 max_length() { return 6; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_SHORT; }
 };
 
 
@@ -499,7 +496,6 @@ public:
   uint32 pack_length() const { return 3; }
   void sql_type(String &str) const;
   uint32 max_length() { return 8; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_MEDIUM; }
 };
 
 
@@ -536,7 +532,6 @@ public:
   uint32 pack_length() const { return 4; }
   void sql_type(String &str) const;
   uint32 max_length() { return 11; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_LONG; }
 };
 
 
@@ -576,7 +571,6 @@ public:
   void sql_type(String &str) const;
   bool can_be_compared_as_longlong() const { return TRUE; }
   uint32 max_length() { return 20; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_LONGLONG; }
 };
 #endif
 
@@ -611,7 +605,6 @@ public:
   uint32 pack_length() const { return sizeof(float); }
   void sql_type(String &str) const;
   uint32 max_length() { return 24; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_FLOAT; }
 };
 
 
@@ -646,7 +639,6 @@ public:
   uint32 pack_length() const { return sizeof(double); }
   void sql_type(String &str) const;
   uint32 max_length() { return 53; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_DOUBLE; }
 };
 
 
@@ -677,7 +669,6 @@ public:
   void sql_type(String &str) const;
   uint size_of() const { return sizeof(*this); }
   uint32 max_length() { return 4; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_NULL; }
 };
 
 
@@ -729,7 +720,6 @@ public:
   }
   bool get_date(TIME *ltime,uint fuzzydate);
   bool get_time(TIME *ltime);
-  field_cast_enum field_cast_type() { return FIELD_CAST_TIMESTAMP; }
   timestamp_auto_set_type get_auto_set_type() const;
 };
 
@@ -753,7 +743,6 @@ public:
   bool send_binary(Protocol *protocol);
   void sql_type(String &str) const;
   bool can_be_compared_as_longlong() const { return TRUE; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_YEAR; }
 };
 
 
@@ -786,7 +775,6 @@ public:
   void sql_type(String &str) const;
   bool can_be_compared_as_longlong() const { return TRUE; }
   bool zero_pack() const { return 1; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_DATE; }
 };
 
 class Field_newdate :public Field_str {
@@ -818,7 +806,6 @@ public:
   bool zero_pack() const { return 1; }
   bool get_date(TIME *ltime,uint fuzzydate);
   bool get_time(TIME *ltime);
-  field_cast_enum field_cast_type() { return FIELD_CAST_NEWDATE; }
 };
 
 
@@ -853,7 +840,6 @@ public:
   void sql_type(String &str) const;
   bool can_be_compared_as_longlong() const { return TRUE; }
   bool zero_pack() const { return 1; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_TIME; }
 };
 
 
@@ -891,7 +877,6 @@ public:
   bool zero_pack() const { return 1; }
   bool get_date(TIME *ltime,uint fuzzydate);
   bool get_time(TIME *ltime);
-  field_cast_enum field_cast_type() { return FIELD_CAST_DATETIME; }
 };
 
 
@@ -937,7 +922,6 @@ public:
   enum_field_types real_type() const { return FIELD_TYPE_STRING; }
   bool has_charset(void) const
   { return charset() == &my_charset_bin ? FALSE : TRUE; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_STRING; }
 };
 
 
@@ -986,7 +970,6 @@ public:
   enum_field_types real_type() const { return FIELD_TYPE_VAR_STRING; }
   bool has_charset(void) const
   { return charset() == &my_charset_bin ? FALSE : TRUE; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_VARSTRING; }
 };
 
 
@@ -1081,7 +1064,6 @@ public:
   uint size_of() const { return sizeof(*this); }
   bool has_charset(void) const
   { return charset() == &my_charset_bin ? FALSE : TRUE; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_BLOB; }
   uint32 max_length();
 };
 
@@ -1111,7 +1093,6 @@ public:
 
   void get_key_image(char *buff,uint length, CHARSET_INFO *cs,imagetype type);
   void set_key_image(char *buff,uint length, CHARSET_INFO *cs);
-  field_cast_enum field_cast_type() { return FIELD_CAST_GEOM; }
 };
 #endif /*HAVE_SPATIAL*/
 
@@ -1155,7 +1136,6 @@ public:
   bool has_charset(void) const { return TRUE; }
   /* enum and set are sorted as integers */
   CHARSET_INFO *sort_charset(void) const { return &my_charset_bin; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_ENUM; }
 };
 
 
@@ -1181,7 +1161,6 @@ public:
   void sql_type(String &str) const;
   enum_field_types real_type() const { return FIELD_TYPE_SET; }
   bool has_charset(void) const { return TRUE; }
-  field_cast_enum field_cast_type() { return FIELD_CAST_SET; }
 };
 
 
@@ -1268,7 +1247,6 @@ int set_field_to_null(Field *field);
 int set_field_to_null_with_conversions(Field *field, bool no_conversions);
 bool test_if_int(const char *str, int length, const char *int_end,
 		 CHARSET_INFO *cs);
-bool field_types_to_be_kept(enum_field_types field_type);
 
 /*
   The following are for the interface with the .frm file