Add column names for metadata when running mysql with -T

Change metadata info so that that MIN() and code MAX() reports that they can return NULL. Bug #324


client/mysql.cc:
  Add column names for metadata when running with -T
mysql-test/r/show_check.result:
  test case for bug fix
mysql-test/t/show_check.test:
  test case for bug fix
sql/item_sum.cc:
  Change metadata info so that that MIN() and code MAX() reports that they can return NULL. Bug #324
sql/sql_load.cc:
  Removed not needed line

client/mysql.cc

@@ -1580,11 +1580,12 @@ print_field_types(MYSQL_RES *result)
   MYSQL_FIELD	*field;  
   while ((field = mysql_fetch_field(result)))
   {
-    tee_fprintf(PAGER,"%s '%s' %d %d %d %d %d\n",
+    tee_fprintf(PAGER,"Name:       '%s'\nTable:      '%s'\nType:       %d\nLength:     %d\nMax length: %d\nIs_null:    %d\nFlags:      %d\nDecimals:   %d\n\n",
 		field->name,
 		field->table ? "" : field->table,
 		(int) field->type,
 		field->length, field->max_length,
+		!IS_NOT_NULL(field->flags),
 		field->flags, field->decimals);
   }
   tee_puts("", PAGER);

mysql-test/r/show_check.result

@@ -212,6 +212,12 @@ select * from t1;
 type_bool	type_tiny	type_short	type_mediumint	type_bigint	type_decimal	type_numeric	empty_char	type_char	type_varchar	type_timestamp	type_date	type_time	type_datetime	type_year	type_enum	type_set	type_tinyblob	type_blob	type_medium_blob	type_long_blob
 0	1	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	20030207100001	0000-00-00	00:00:00	0000-00-00 00:00:00	NULL	NULL	NULL	NULL	NULL	NULL	NULL
 drop table t1;
+create table t1 (a int not null);
+create table t2 select max(a) from t1;
+show columns from t2;
+Field	Type	Null	Key	Default	Extra
+max(a)	bigint(20)	YES		NULL	
+drop table t1,t2;
 create table t1 (c decimal, d double, f float, r real);
 show columns from t1;
 Field	Type	Null	Key	Default	Extra

mysql-test/t/show_check.test

@@ -114,6 +114,13 @@ insert into t1 (type_timestamp) values ("2003-02-07 10:00:01");
 select * from t1;
 drop table t1;
 
+#
+# Check metadata
+#
+create table t1 (a int not null);
+create table t2 select max(a) from t1;
+show columns from t2;
+drop table t1,t2;
 
 # Check auto conversions of types
 

sql/item_sum.cc

@@ -46,7 +46,11 @@ Item_sum::Item_sum(List<Item> &list)
 void Item_sum::make_field(Send_field *tmp_field)
 {
   if (args[0]->type() == Item::FIELD_ITEM && keep_field_type())
+  {
     ((Item_field*) args[0])->field->make_field(tmp_field);
+    if (maybe_null)
+      tmp_field->flags&= ~NOT_NULL_FLAG;
+  }
   else
   {
     tmp_field->flags=0;
@@ -158,7 +162,8 @@ Item_sum_hybrid::fix_fields(THD *thd,TABLE_LIST *tables)
   else
     max_length=item->max_length;
   decimals=item->decimals;
-  maybe_null=item->maybe_null;
+  /* MIN/MAX can return NULL for empty set indepedent of the used column */
+  maybe_null= 1;
   binary=item->binary;
   unsigned_flag=item->unsigned_flag;
   result_field=0;

sql/sql_load.cc

@@ -165,7 +165,6 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   }
   else
   {
-    read_file_from_client=0;
 #ifdef DONT_ALLOW_FULL_LOAD_DATA_PATHS
     ex->file_name+=dirname_length(ex->file_name);
 #endif