added collation processing in UNION merging

temporary table BLOB now is longblob


mysql-test/r/create.result:
  blob size changed for safety
mysql-test/r/type_blob.result:
  blob size changed for safety
mysql-test/r/type_ranges.result:
  blob size changed for safety
mysql-test/r/union.result:
  blob size changed for safety
  new tests of UNION types merging
mysql-test/t/union.test:
  new tests of UNION types merging
sql/field.h:
  blob size changed for safety
sql/item.cc:
  processing of collation added
  added comment
sql/item.h:
  joining of UNION fields may failed now, because of incompatibility of collations
sql/sql_union.cc:
  joining of UNION fields may failed now, because of incompatibility of collations

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/field.h b/sql/field.h
index cb44ab76439..0b6ba7dde09 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -941,7 +941,7 @@ public:
 	     struct st_table *table_arg, CHARSET_INFO *cs)
     :Field_str((char*) 0,len_arg, maybe_null_arg ? (uchar*) "": 0,0,
 	       NONE, field_name_arg, table_arg, cs),
-    geom_flag(true), packlength(3)
+    geom_flag(true), packlength(4)
     {
       flags|= BLOB_FLAG;
     }